The book essentially consists of three parts:
Having re-iterated the duty to follow the mitzvah, Joshua orders the Israelites to set forth, and they leave Shittim. When they reach the Jordan River, Joshua states that the Ark will miraculously cross the Jordan. As soon as the Ark reaches the river, a miracle duly occurs, and the river stops flowing and rapidly dries up, so the priests carrying it halt, allowing the rest of the Israelites to cross as well. In commemoration of the event, Joshua orders two monuments to be erected: one in the river-bed; the other on the western bank, where the Israelites encamp.
The Israelites are circumcised at Gibeath-Haaraloth (translating as hill of foreskins). Those who had been born in the desert had not been circumcised. The people are therefore circumcised, and the area is named Gilgal in memory (Gilgal sounds like Gallothi - I have removed, but is more likely to translate as circle of standing stones).
The Israelites then commence with the Battle of Jericho. Placing Jericho under siege, the Israelites circle it once a day for six days, and on the seventh make seven circuits, each time loudly blowing horns and shouting. On the final circuit, the walls cave in, and the inhabitants, except Rahab and her family, are slaughtered. A curse is pronounced against rebuilding the city.
Ai is surveyed and pronounced weak, so the Israelite army sends only a small group to attack them. However they are defeated, causing Joshua and the people to despair. But God announces that the people have sinned: someone has stolen some of the spoils from Jericho which are meant to be for the temple. Consequently the Israelites set out to discover the sinner by casting lots, whittling them down first by tribe (Judah), then clan (Zarhites), then sept (Zabdi), then finally detecting it as Achan. Achan admits having taken a costly Babylonian garment, besides silver and gold, and his confession is verified by the finding of the treasure buried in his tent, so Achan is taken into the valley of Achor, where he and his household are stoned and burned to death. Afterwards, 30,000 Israelites set an ambush of Ai overnight, and in the morning another Israelite force attack and then feign retreat, drawing the forces of Ai far away from the city. When Joshua raises his lance, the 30,000 men preparing the ambush strike, while Joshua starts attacking again, thus surrounding Ai's forces. The entire city is burned and its inhabitants slaughtered. The king of Ai, however, is taken alive and delivered to Joshua. He is then impaled on a stake for public display before being buried outside the city gates, following Hebrew guidelines for the guilty. (see Deuteronomy 21.23).
Joshua erects an altar on Mount Ebal and makes offerings upon it and carves into it the law of Moses. The people are arranged into two sections, with one facing Ebal and the other facing Gerizim. They each read the blessings and curses specified in Deuteronomy as appropriate.
The Hivites fool the Israelites into thinking them foreigners and gain a non-aggression treaty from the Israelites. Even after its detection, the fraud is not abrogated, though the Hivites are punished by being treated as the lowest social class (referred to via the Hebrew idiom "hewers of wood and drawers of water for the altar of Yhwh"). Adonizedek, king of Jerusalem, brings about an alliance of the "five kings of the Amorites" (the kings of Hebron, Jarmuth, Lachish, and Eglon, and himself), and they besiege the Hivites in Gibeon, whom they perceive as traitors. The Hivites implore Joshua's help, and so he launches a surprise attack following a night march, causing the Amorites to panic and flee as far as Beth-horon. A poem is quoted from the Book of Jasher, which states that the sun stood still at Gibeon, and the moon in the valley of Ajalon, in order that Joshua could complete the battle. Despite the five kings' cowardly attempt at avoiding retribution by hiding inside a cave, they are discovered and trapped there until their army has been completely obliterated. Afterwards, the kings are brought to Joshua, who first humiliates them, then orders their death and has them impaled for public display. At sunset, the bodies are thrown back into the cave from which they hid, and the entrance sealed.
Jabin, king of Hazor, his army, and his vassals, rendezvous at Merom. Joshua, however, executes a swift attack and is able to defeat them. Pursuing them to a great distance, he hamstrings their horses, burns their chariots, captures Hazor, slaughters its inhabitants, and burns it to the ground. Lesser royal residences are also captured and their inhabitants slaughtered, although the cities on the hill remain.
Although early archaeological excavations seemed to support the historicity of Joshua, for example by finding destruction layers in several tells (the archaeological remains) of prominent sites such as Jericho, the conclusion that such destruction must have been caused by Joshua has since been criticised as Bible and Spade - using the Bible to interpret the remains, rather than using archaeological methods to interpret the remains and thus determine their relationship to the Biblical account.
At many points in the Tanakh God orders men to kill other people for their faithlessness including at the scene of the golden calf when 4,000 Jews were slain for idolatry.
Liberal theologians see this as an ethically unjustifiable order to commit genocide, which is inconsistent with the overall view in the Hebrew and Christian scriptures of God as a loving, compassionate Creator. They see it as a theological polemic, with the majority of events invented during or after the Babylonian captivity, to encourage faithfulness to the Jewish creed at a time when it was being threatened. For instance, Morton says that Joshua "should be understood as a rite of ancient peoples (Israel among them) whereby within the context of their times, they attempted to please God (or the gods)".
Conservative theologians, who see the book as a historically accurate account written during or soon after the life of Joshua, give one of the following explanations to this problem:
Jewish tradition ascribes authorship of the book to Joshua, and consequently places its origin at the time of the supposed Israelite invasion (which biblical chronology places in either the 15th or 13th century BC). Some opinions presented in the Talmud state that the book was written by Joshua except for the last verses (24:29-33) which were added by Phinehas the priest; other Classical Rabbinical writers took a different stance.
Certainly, the author presents himself as an eyewitness to the accounts described, occasionally using first person pronouns (for instance, in Joshua 5:1), although Joshua is usually described in the third person. Some sections (eg. , , ), even according to Jewish tradition, could however only have been added after Joshua's death; tradition normally ascribes these sections to Eleazar or Phinehas (Eleazar's son). Also problematic is the frequently used phrase to this day, suggesting a substantial amount of time between the events and the account being written.
Despite there being a Jewish tradition of authorship, in Christian circles, both Catholic and Protestant, the authorship has been considered dubious since ancient times. Theodoret proposed that it was written by a later author who had access to documents from Joshua's time, while Athanasius argued that the ascription to Joshua was merely indicative of the main hero of the text. Alphonsus Tostat (1613) argued that Solomon was the real author, and Maes (1574) claimed that it might have been Ezra, particularly since he had access to Hebrew archives.
In modern times, religiously conservative Jewish scholars continue to generally adhere to the traditional view, arguing that the book was written by a contemporary of Joshua, and their view has also been adopted by some evangelical Protestants. However, with the advent of source criticism, some scholars now reject claims of authorship by Joshua or his contemporaries.
Instead of the traditional Jewish view, most modern scholars have suggested several alternative and related possibilities, arguing that the Book of Joshua must be regarded as a compilation. An analysis of its contents makes it certain, in the eyes of scholars, that its sources are of the same character as those of the Pentateuch. Despite the Jewish tradition of authorship, the view of modern scholars was also the impression of classical Rabbis, to a certain degree; according to Mak. 11a, the chapter concerning the cities of refuge (Joshua 20) was taken from the Pentateuch. Classical Rabbinical writings refer to Joshua as having been written in the light of the Deuteronomic legislation (Genesis Rashi 6:14).
Scholars now believe that Joshua is a continuation of the JE version of the torah, and thus two of the main spliced-together narrative sources within it - Jahwist (J), and Elohist (E) - or at least deriving from sources from the same schools of thought as these. The Deuteronomist is considered to have detached the Joshua section of this at some later point and embedded it within the Deuteronomic history, making a number of minor edits and framing additions (mainly Joshua , , , and ). Thus the work would be mainly the work of writers from the 8th and 7th century, but with retouchings from the exilic period.
The form of this modern theory that argues for the sources being J and E, rather than from similar schools, is known as the hexateuch theory, since the first six books would have been the original narrative unit). Although, given their narrative, it is probable that J, E, and P (the Priestly source), continued their narrative as far as the conquest of the land, the books of Ezra and of Nehemiah give no intimation of the existence of a hexateuch. Nevertheless, a number of scholars have argued that Hosea, Amos, and Micah, were aware of a hexateuch-like JE source, due to passages such as Micah +, Hosea , +, and Amos , , .