The 17 hymns of the Gathas consist of 238 verses, of about 1300 lines or 6000 words in total. They were later incorporated into the 72-chapter Yasna (chapter: ha or had, from the Avestan ha'iti, 'cut'), which in turn is the primary liturgical collection of texts within the greater compendium of the Avesta. The 17 hymns are identified by their chapter numbers in the Yasna, and are divided into five major sections:
|28–34||Ahunavaiti Gatha||(cf. Ahuna Vairya), 100 stanzas, (3 verses, 7+9 syllable meter)|
|43–46||Ushtavaiti Gatha||'Having Happiness', 66 stanzas (5 verses, 4+7 syllable meter)|
|47–50||Spenta Mainyu Gatha||'Bounteous Spirit', 41 stanzas (4 verses, 4+7 syllable meter)|
|51||Vohu Khshathra Gatha||'Good Dominion', 22 stanzas (3 verses, 7+7 syllable meter)|
|53||Vahishto Ishti Gatha||'Best Beloved', 9 stanzas (4 verses, two of 7+5 and two of 7+5+5 syllables)|
With the exception of Ahunavaiti Gatha, which is named after the Ahuna Vairya prayer (Yasna 27, not in the Gathas), the names of the Gathas reflect the first word(s) of the first hymn within them. The meter of the hymns is historically related to the Vedic tristubh-jagati family of meters. Hymns of these meters are recited, not sung.
The sequential order of the Gathas is structurally interrupted by the Yasna Haptanghaiti ("seven-chapter Yasna", chapters 35-41, linguistically as old as the Gathas but in prose) and by two other minor hymns at Yasna 42 and 52.
It must be noted that the Gathas are in an otherwise unknown language. The dependency on Vedic Sanskrit is a significant weakness in the interpretation of the Gathas, as the two languages, though from a common origin, had developed independently. Sassanid era translations and commentaries (the Zend) have been used to interpret the Gathas, but by the 3rd century the Avestan language was virtually extinct, and a dependency of the medieval texts is often discouraged as the commentaries are frequently conjectural. While some scholars argue that an interpretation using younger texts is inadvisable (Geldner, Humbach), others argue that such a view is excessively skeptical (Spiegel, Darmesteter). The risks of mis-interpretation are real, but lacking alternates, such dependencies are perforce necessary.
"The Middle Persian translation seldom offers an appropriate point of departure for a detailed scholarly approach to the Gathas, but an intensive comparison of its single lines and their respective glosses with their Gathic originals usually reveals the train of thought of the translator. This obviously reflects the Gatha interpretation by the priests of the Sasanian period, the general view of which is closer to the original than what is sometimes taught about the Gathas in our time."
There are four monumental translations of the Gathas worth noting: The earlier James Darmesteter version (Le Zend-Avesta, 1892-1893) which is based on a translation "from below", that is, based on the later middle Persian commentaries and translations. The other three are Christian Bartholomae's Die Gathas des Awesta (1905, Strassburg: Trübner), Helmut Humbach's The Gathas of Zarathushtra (1959, Heidelberg: Winter), and Stanley Isler's The Gathas of Zarathustra'' (1975, Acta Iranica IV, Leiden: Brill). These three texts exploit the "Vedic" approach, and Bartholomae's was the first of its kind.
The problems that face a translator of the Avestan Gathas are significant: "No one who has ever read a stanza of [the Gathas] in the original will be under any illusions as to the labour which underlies the effort [of translating the hymns]. The most abstract and perplexing thought, veiled further by archaic language, only half understood by later students of the seer's own race and tongue, tends to make the Gathas the hardest problem to be attempted by those who would investigate the literary monuments."
Other verses, from which some aspects of Zoroaster's life have been inferred, are semi-(auto)biographical, but all revolve around Zarathustra's mission to promote his view of the Truth (again Asha). For instance, some of the passages describe Zarathustra's first attempts to promote the teachings of Ahura Mazda, and the subsequent rejection by his kinsmen. This and other rejection led him to have doubts about his message, and in the Gathas he asked for assurance from Ahura Mazda, and requests repudiation of his opponents.
The various hymns appear to have been composed at different periods in his life, and read chronologically, a certain earnestness and conviction in his message are apparent. While in earlier verses, Zarathustra occasionally expresses his doubts on his own suitability of the mission, he never wavers in his conviction that the message is correct. A tone of contentment and belief in his vindication is apparent only in the last few hymns, and to the last, where he officiates at the wedding of his youngest daughter, he remains the persevering predicant.
Aspects of Zoroastrian philosophy are distributed over the entire collection of Gathas. There is no systematic arrangement of doctrine in the texts.