Jesus' real name would have been something like Yeshuah ben Yosef. He lived in Palestine between about 7 b.c.e. and 26 c.e. His life is shrouding in myth and hyperbole and very little can be said for certain about him, other than that he was executed by the Roman goovernment of the time for sedition. He seems to have been a religious prophet and political agitator, possibly a member of the Pharisee sect of Judaism (the idea that he was an Essene can safely be rejected as a contemporary myth/meme). Perhaps he was enlightened being. Perhaps he was an avatar. One thing that is certain is that he was not responsible for the sect that later bore his name. That devastatingly successful meme, known as Christianity, was pretty much the work of Paul of Tarsus, a convert who never met Yeshuah in person.
Although Jesus is probably the single most important individual in human history (even if only indirectly, through the religion that later developed in his name), all that we know of him is gleaned from a set of extremely unreliable texts known as the Gospels. There are no unambiguous independent (i.e. non-Christian) contemporary accounts of his life or teachings. (A short passage in Josephus - a contemporary Jewish historian - which refers to Jesus, may or may not be a forgery, a later Christian interpolation) [note]. Thus one who wishes to arrive at an understanding of his real life and teachings must painstakingly comb through the Gospels, in order to extract those few authentic fragments that can be found in them. And even then, we can never be truely sure. (There is a large amount of scholarly literature on Biblical Criticism [by which is meant a careful analysis of the Gospel texts, the way in which they were written, what is original and what a later interpolation, etc], and the problems of arriving at the "historical Jesus", as opposed to the Jesus of theology and of belief. There are also some good books on the latter question. See e.g. Joel Carmichael, The Death of Jesus, Penguin, 1962; Hugh J Schonfield, The Passover Plot, Hutchinson, 1965, and other works by the same author; S. G. F. Brandon, The Trial of Jesus of Nazareth, Batsford, 1968; and, for a somewhat extreme (and to my mind not very bleiveable, but still who is to say?) opinion there is Michael Baigent, Richard Leigh, and Henry Lincoln, The Messianic Legacy, Corgi, 1986)
Regarding this contentious issue, here are some links
Although to say the passage in Josephus is definitely an interpelation would be incorrect, there are still grounds for scepticism, and I feel we can confidentally say that the words as they appear in the Testimonium Flavianum are either a complete interpolation or a corruption of whatever was previously there.
Buddha and Christ - Two Gods on the Path to Humanity