The Silmarillion comprises five parts. The first part, Ainulindalë, tells of the creation of Eä, the world. Valaquenta, the second part, gives a description of the Valar and Maiar, the supernatural powers in Eä. The next section, Quenta Silmarillion, which forms the bulk of the collection, chronicles the history of the events before and during the First Age. The fourth part, Akallabêth, relates the history of the Downfall of Númenor and its people, which takes place in the Second Age. The final part, Of the Rings of Power and the Third Age, is a brief account of the circumstances which led to and were presented in The Lord of the Rings.
The five parts were initially separate works, but it was the elder Tolkien's express wish that they be published together. Because J. R. R. Tolkien died before he finished revising the various legends, Christopher gathered material from his father's older writings to fill out the book. In a few cases, this meant that he had to devise completely new material in order to resolve gaps and inconsistencies in the narrative.
The Silmarillion, like Tolkien's other Middle-earth writings, was meant to have taken place at some time in Earth's past. In keeping with this idea, The Silmarillion is meant to have been translated from Bilbo's three-volume Translations from the Elvish, which he wrote while at Rivendell.
Among the notable chapters in the book are:
The inside title page contains an inscription written in Tengwar. In the common script, it reads "The tales of the First Age when Morgoth dwelt in Middle-Earth and the Elves made war upon him for the recovery of the Silmarils to which are appended the downfall of Númenor and the history of the rings of power and the Third Age in which these tales come to their end."
The first section of The Silmarillion, Ainulindalë ("The Music of the Ainur"), takes the form of a primary creation myth. Ilúvatar ("Father of All") first created the Ainur, a group of eternal spirits or demiurges, called "the offspring of his thought". Ilúvatar brought the Ainur together and showed them a theme, from which he bade them make a great music. Melkor—whom Ilúvatar had given the "greatest power and knowledge" of all the Ainur—broke from the harmony of the music to develop his own song. Some Ainur joined him, while others continued to follow Ilúvatar, causing discord in the music. This happened thrice, with Eru successfully overpowering his subordinate with a new theme each time. Ilúvatar then stopped the music and showed them a vision of Arda and its peoples. The vision disappeared after a while, and Ilúvatar offered the Ainur a chance to enter into Arda and govern over the new world.
Many Ainur descended, taking physical form and becoming bound to that world. The greater Ainur became known as Valar, while the lesser Ainur were called Maiar. The Valar attempted to prepare the world for the coming inhabitants (Elves and Men), while Melkor, who wanted Arda for himself, repeatedly destroyed their work, until, slowly, through waves of destruction and creation, the world took shape.
Valaquenta ("Account of the Valar") describes Melkor and each of the fourteen Valar in detail, as well as a few of the Maiar. It also tells how Melkor seduced many Maiar—including Sauron and the Balrogs—into his service.
Quenta Silmarillion ("The History of the Silmarils"), which makes up the bulk of the book, is a series of interconnected tales set in the First Age making up the tragic saga of the three magical jewels, the Silmarils. The Valar had attempted to fashion the world for Elves and Men, but Melkor continually destroyed their handiwork, so they removed to Aman, a continent to the west of Middle-earth, where they established their home called Valinor. When the Elves awoke, the Valar decided to fight Melkor to keep them safe. They defeated and captured Melkor, and invited the Elves to come to Aman. Many Elves journeyed to Aman, but some did not attempt the journey, and others stopped along the way. Of the three tribes that set out, all of the Vanyar and Noldor, and most of the Teleri reached Aman. While in Aman, a Noldorin Elf named Fëanor created the Silmarils, which contained the light of the Two Trees of Valinor, the light source of Aman. Melkor, having been released after seeming to repent, stole the Silmarils, killed Fëanor's father, and destroyed the Two Trees. Fëanor and his sons swore an oath of revenge against Melkor and anyone who kept a Silmaril from them, and led many of his kin to Middle-earth, where Melkor had fled, killing some of the Teleri for their ships.
When Melkor arrived in Middle-earth, he attacked the Elvish kingdom of Doriath, but was defeated. This battle was the first of five battles between Melkor and the Elves, aided at times by Men and Dwarves. This conflict came to be known as the War of the Jewels. Soon, the Noldor arrived in Middle-earth and attacked Melkor, and though Fëanor was slain, they were victorious. After a peace, Melkor again attacked the Noldor, but was defeated and besieged. Nearly four hundred years later, Melkor broke the siege and drove the Noldor back. A man named Beren survived the battle and wandered to Doriath, where he fell in love with Lúthien, the king's daughter. The king would only allow their marriage if Beren gave him a Silmaril. Together, Beren and Lúthien sneaked into Melkor's fortress and stole a Silmaril, which Beren gave to the king. The Noldor, seeing that Melkor was not invincible, attacked again, but were utterly defeated, due in part to the treachery of Men. All of the Elvish kingdoms fell, until Eärendil the half-Elven, using the light of the Silmaril Beren retrieved, travelled across the sea to Aman to ask the Valar for help. The Valar agreed; they attacked and defeated Melkor, completely destroying his fortress Angband and sinking the land of Beleriand, and expelled him from Arda. This ended the First Age of Middle-earth.
Akallabêth ("The Downfallen") comprises about thirty pages, and recounts the rise and fall of the island kingdom of Númenor, which the Valar gave as a gift to the three loyal houses of Men who had aided the Elves in the war against Melkor after his defeat. The fall of Númenor is brought about in large measure by the influence of the evil Maia Sauron (formerly the chief servant of Melkor), who had arisen during the Second Age and tried to take over Middle-earth. The Númenóreans moved against Sauron, who, seeing that he could not defeat the Númenóreans with force, allowed himself to be taken prisoner to Númenor, where he quickly seduced the king, Ar-Pharazôn, led the Númenóreans into worshipping his former master, and urged them to wage war on the Valar themselves. Ar-Pharazôn created a fleet and sailed to Aman, but his campaign ended with the destruction of the fleet and the drowning of Númenor by Ilúvatar, in punishment for their rebellion against the rightful rule of the Valar. Sauron, however, escaped and returned to Middle-earth. Some Númenóreans remained loyal to the Valar and also fled to Middle-earth, where they founded the kingdoms of Arnor and Gondor.
The concluding section of the book, comprising about twenty pages, describes the events that take place in Middle-earth during the Second and Third Ages. In the Second Age, Sauron emerged as the main power in Middle-earth, and the Rings of Power were forged by Elves led by Celebrimbor. Sauron secretly forged his own ring to control the others, which led to war between the peoples of Middle-earth and Sauron, culminating in the War of the Last Alliance, in which Elves and the remaining Númenóreans united to defeat Sauron, bringing the Second Age to an end. The Third Age opens with the passing of the One Ring to Isildur, who is ambushed at the Gladden Fields shortly after, causing the loss of the One Ring. This section also gives a brief overview of the events leading up to and taking place in The Lord of the Rings, including the waning of Gondor, the re-emergence of Sauron, the White Council, Saruman's treachery, and Sauron's final destruction along with the One Ring.
At the time, he called his collection of nascent stories The Book of Lost Tales, which became the name for the first two volumes of The History of Middle-earth. The stories in The Book of Lost Tales were told through the medium of a mariner named Eriol (in later versions, an Anglo-Saxon named Ælfwine) who found the island of Tol Eressëa, where the Elves told him their history. However, Tolkien never completed The Book of Lost Tales before he left it to compose the poems "The Lay of Leithian" and "The Lay of the Children of Húrin".
The first complete version of The Silmarillion was the 'Sketch of the Mythology' written in 1926. The 'Sketch of the Mythology' was a 28-page synopsis intended to explain the background of the story of Túrin to R. W. Reynolds, a friend to whom Tolkien had sent several of his stories. From the 'Sketch' Tolkien developed a fuller narrative version of The Silmarillion called Quenta Noldorinwa. The Quenta Noldorinwa was the last complete version of The Silmarillion Tolkien ever wrote.
In 1937, encouraged by the success of The Hobbit, Tolkien submitted an incomplete but more fully developed version of The Silmarillion, called Quenta Silmarillion, to his publisher, George Allen & Unwin, but they rejected the work as being obscure and "too Celtic". The publisher instead asked Tolkien to write a sequel to The Hobbit. Tolkien began to revise The Silmarillion, but soon turned his full attention to writing the sequel, which would become The Lord of the Rings. He renewed work on The Silmarillion after completing The Lord of the Rings, and he greatly desired to publish the two works together. But when it became clear that would not be possible, Tolkien turned his full attention back to preparing The Lord of the Rings for publication.
In the late 1950s Tolkien again began work on The Silmarillion, but much of his writing from this time was more concerned with the theological and philosophical underpinnings of the work than with narratives themselves; by this time, he had doubts about some of the fundamental aspects of the work that went back to the earliest versions of the stories, and it seems that he felt the need to solve these problems before he could produce the "final" version of The Silmarillion. During this time he wrote extensively on such topics as the nature of evil in Arda, the origin of Orcs, the customs of the Elves, the nature and means of Elvish rebirth, and the "flat" world and the story of the Sun and Moon. In any event, with one or two exceptions, he wrought little change to the narratives during the remaining years of his life.
For several years after his father's death, Christopher Tolkien compiled a Silmarillion narrative. Christopher's intentions seem to have been mostly to use the latest writings of his father's that he could, and to keep as much internal consistency (and consistency with The Lord of the Rings) as possible, though he admitted that a complete consistency was impossible. As explained in The History of Middle-earth, Christopher drew upon numerous sources for his narrative, relying on post-Lord of the Rings works where possible, but ultimately reaching back as far as the 1917 Book of Lost Tales to fill in portions of the narrative which his father had planned to write but never addressed. In one later chapter of Quenta Silmarillion, "Of the Ruin of Doriath", which had not been touched since the early 1930s, he had to construct a narrative practically from scratch. The final result, which included genealogies, maps, an index, and the first-ever released Elvish word list, was published in 1977.
Due to Christopher's extensive explanations (in The History of Middle-earth) of how he compiled the published work, much of The Silmarillion has been debated by readers. Christopher's task is generally accepted as very difficult given the state of his father's texts at the time of his death: some critical texts were no longer in the Tolkien family's possession, and Christopher's task compelled him to rush through much of the material. Christopher reveals in later volumes of The History of Middle-earth many divergent ideas which do not agree with the published version. Christopher Tolkien has suggested that, had he taken more time and had access to all the texts, he might have produced a substantially different work. But he was compelled by considerable pressure and demand from his father's readers and publishers to produce something publishable as quickly as possible. Some contend that parts of The Silmarillion are more a product of the son than of the father, and as such its place in the Middle-earth canon is hotly debated in certain circles.
In October 1996, Christopher Tolkien commissioned illustrator Ted Nasmith to create full-page full-colour artwork for the first illustrated edition of The Silmarillion. It was published in 1998, and followed in 2004 by a second edition featuring corrections and additional artwork by Nasmith.
During the 1980s and 1990s, Christopher Tolkien published most of his father's Middle-earth-related writings as the 12-volume The History of Middle-earth series. In addition to the source material and earlier drafts of several portions of The Lord of the Rings, these books greatly expand on the original material published in The Silmarillion, and in many cases diverge from it. There is much that Tolkien intended to revise but only sketched out in notes, and some new texts surfaced after the publication of The Silmarillion. These books also make it clear just how unfinished the later parts of The Silmarillion really were: some parts were never rewritten after the early versions in Lost Tales.
Greek mythology also colours the Valar, who borrow many attributes from the Olympian gods. The Valar, like the Olympians, live in the world, but on a high mountain, separated from mortals; But the correspondences are only approximate; the Valar also contain elements of Norse mythology. Several of the Valar have characteristics resembling various Æsir, the gods of Asgard. Thor, for example, physically the strongest of the gods, can be seen both in Oromë, who fights the monsters of Melkor, and in Tulkas, the physically strongest of the Valar. Manwё, the head of the Valar, exhibits some similarities to Odin, the "Allfather". Tolkien also said that he saw the Maia Gandalf as an "Odinic wanderer".
Influence of the Bible and traditional Christian narrative are seen in The Silmarillion in the conflict between Melkor and Eru Ilúvatar, a parallel of the polarity of Lucifer and God. Further, The Silmarillion tells of the creation and fall of the Elves, as Genesis tells of the creation and fall of Man. As with all of Tolkien's works, The Silmarillion allows room for later Christian history, and one version of Tolkien's drafts even has Finrod, a character in The Silmarillion, speculating on the necessity of Eru's (God's) eventual Incarnation to save humankind.
Celtic legends show their influence in the exile of the Noldorin Elves, for example, that borrow elements from the story of the Tuatha Dé Danann. Welsh influence is seen in the Elvish language Sindarin, that Tolkien gave "a linguistic character very like (though not identical with) British-Welsh ... because it seems to fit the rather 'Celtic' type of legends and stories told of its speakers".
Despite these shortcomings, a few reviewers praised the scope of Tolkien's creation. The New York Times Book Review acknowledged that "what is finally most moving is … the eccentric heroism of Tolkien's attempt". TIME described The Silmarillion as "majestic, a work held so long and so powerfully in the writer's imagination that it overwhelms the reader". The Horn Book Magazine even lauded the "remarkable set of legends conceived with imaginative might and told in beautiful language".
Some reviewers, however, had nothing positive to say about the book at all. The New York Review of Books called The Silmarillion "an empty and pompous bore", "not a literary event of any magnitude", and even claimed that the main reason for its "enormous sales" were the "Tolkien cult" created by the popularity of The Hobbit and The Lord of the Rings. The School Library Journal called it "only a stillborn postscript" to Tolkien's earlier works. Peter Conrad of The New Statesman even went so far as to say that "Tolkien can't actually write".