Shwa:
There are a number of excellent studies concerning not only authorship, but also date. The following link is just one.
It is common among the intelligentsia to cast aspersions upon both authorship and dating, but invariably those who do run into several brick walls that they choose not to see.
Of first consideration is that the early (2nd century) church fathers and leaders without fail attributed the gospels to their named authors. Implicit in this attribution is the understanding that in all probability, each of the "authors" (with the possible exception of Luke) had an "amanuensis", or scribe who actually did the writing, while the "author" dictated the text.
Secondly, there is NO extant evidence of any type to support the contention of anonymous authorship, or even the late dates presumed by some.
Third, in the majority of the cases where authorship is questioned, it is based upon a presupposition....that being that in the body of the text are written details of events that occurred AFTER the death of the alleged author, and it would have been impossible for the author to know of the events. The presupposition is that prophecy (FORE-telling), which is supernatural in origin, is not possible.
The best example that can be given is the approach of the Jesus Seminar "scholars", who claim that Jesus never said anything at all about the destruction of Jerusalem (detailed by Matthew in Mat. 24), therefore the book of Matthew could only have been written post 70 AD, and therefore could not have been Matthew, since he was believed to have been martyred around 62-65 AD.
I have found that most of the arguments against traditional authorship or dating are founded upon rather specious arguments and faulty reasoning, not solid scholarship.
The Gospel of Matthew
Author