The Gospel of Thomas, completely preserved in a papyrus Coptic manuscript discovered in 1945 at Nag Hammadi, Egypt, is a list of 114 sayings attributed to Jesus. Some of those sayings resemble those found in the four canonical Gospels (Matthew, Mark, Luke, and John), but other sayings were unknown until its discovery.
Unlike the four canonical gospels, which employ narrative accounts of the life of Jesus, Thomas takes the less structured form of a collection of sayings attributed to Jesus and brief dialogues with Jesus and some of his disciples reported to Didymus Judas Thomas without being embedded in any narrative nor worked into any philosophical or rhetorical context.
When the complete text was found, in a Coptic version, it was realized that three separate Greek portions of it had already been discovered in Oxyrhynchus, Egypt in 1898. The manuscripts bearing the Greek fragments of the Gospel of Thomas have been dated to about 200, and the manuscript of the Coptic version to about 340. Although the Coptic version is not quite identical to any of the Greek fragments, it is believed that the Coptic version was translated from a prior Greek version.
The Gospel of Thomas as heresy
Because the Gospel of Thomas has a late date, this helps scholars to understand how it may have been written. A comparison shows a high probability of copying that took place between the writer of the Gospel of Thomas and the four canonical Gospels. It can be shown that a kind of mysticism has invaded the text, as well as the authors intent to use Thomas' name as a title of the document in hopes that it would gain widespread acceptance. One of the more harmful sayings within the text are the last two verse (113-114 - see "Quotes" below). Proponents of the Gospel of Thomas try and explain this as a later addition to the text, however this is mere speculation. Christians can safely conclude that the Gospel of Thomas is a document that teaches heretical ideas concerning Jesus, hence why it was not accepted in the canon of Scripture.
(113) His disciples said to him, "When will the kingdom come?" Jesus said, "It will not come by waiting for it. It will not be a matter of saying 'here it is' or 'there it is.' Rather, the kingdom of the father is spread out upon the earth, and men do not see it."
(114) Simon Peter said to him, "Let Mary leave us, for women are not worthy of life." Jesus said, "I myself shall lead her in order to make her male, so that she too may become a living spirit resembling you males. For every woman who will make herself male will enter the kingdom of heaven." 
- Patterson-Meyer Translation
- Thomas Lambdin Translation
- Patterson and Robinson Translation
- Gospel of Thomas Collection at The Gnosis Archive
- Patterson-Meyer Translation
- Brill Literal Translation
- Gospel of Thomas: comparative translations with commentary
- Coptic Interlineal Gospel of Thomas
- Gospel of Thomas - Many Translations and Resources
- The Nag Hammadi Library