It just came to my attention that Paul Foster (editor and contributor to the fine volume The Non-Canonical Gospels, mentioned HERE) has published a volume in the Very Short Introduction series on The Apocryphal Gospels. More information can be found on Amazon.
Earlier this month April DeConick mentioned on her blog, the Forbidden Gospels, a series of articles from the Expository Times on apocryphal gospels. You can see her original post HERE. I mention this post now because, thanks to April, I have been asked to contribute a piece on the Infancy Gospel of Thomas. These articles run about 6000 words, thus representing a decent introduction to the text and to current scholarship. If you do not have access to the journal, there will be a collection available next year similar to the volume by Paul Foster on the Apostolic Fathers (The Writings of the Apostolic Fathers).