There's a lot of occultic teachers that'll say that Jesus never existed and that'll say that the 4 Gospels are constructions over the first few hundred years of Christianity as pagan myth was ransacked by the Romans to produce this new religion. But there's too many references outside of the New Testament in the first century to Jesus, like Josephus, Tacitus, Seneca, Nero, Philo, Pliny and various others that mention Jesus.
Lots of the books that'll be cited that Jesus never existed either as primary sources or in recently published books were books written during the Enlightenment prior to all of the major discoveries of the 19th and 20th centuries to the contrary.
A great book to get your hands on with evidences is a book by Josh McDowell called "More Than A Carpenter." He's also got two or three volumes with the title "Evidence That Demands A Verdict." What I like about the "More Than A Carpenter" book is that it's small and can be read in an evening or two, or a third at the most if your homework load with school was just impossible. I'm genuinely not sure if it's the whole book because google books isn't dial-up friendly, but here's the google version at google books, although it might just be teaser rather than the whole book:
More Than A Carpenter at google books
