Outline - F. F. Bruce - The New Testament Documents: Are They Reliable? (PDF)
This little Inter-Varsity classic has been republished more times than a person can count—and for good reason. Clear, readable, definitive and written for the interested layman (and his friends!) Absolutely the opposite of "for specialists only."
The back of an old copy has the following text:
"Fact or fabrication? Christianity is founded upon historical events. If the claims and life of Jesus Christ are mere fabrications, Christianity collapses. Since the New Testament is the primary historical source, its reliability is a crucial issue in any discerning evaluation of Christianity. This book presents in readable form the results of modern research and sound historical scholarship."
This book is worth reading for grasp of the basic eisogogical questions: Who wrote that Gospel? How do we know that he did? and so on. Or, what is the evidence that Paul wrote the letters which bear his name? Same for Peter. Why, when Luke was not one of the twelve, are his Gospel and the Book of the Acts included in the New Testament canon?
If you have questions like these, there is no better short book to begin with than F.F. Bruce's. And you will probably do well to buy more than one copy, because you will end up loaning it out to more than a few people!