Is it true that Jesus never existed as many claim? And if his historicity is accepted, how do we know what he really said or did? Are there systems or methods to find out what is historical and what is not in what is told about Jesus? What is the value of texts, the Gospels, that have been transmitted to us since ancient times? Or also, how can you get something that comes close to the truth of as much as it has been written about Jesus, especially since the time of the Enlightenment? And finally, why do scholars in general seem to arbitrarily reject passages from the gospels as "false" and accept others as "true"? All these are real questions, formulated to the author directly and personally, that arise spontaneously in anyone who is interested in Jesus. Throughout the book the reader will perceive how using scientifically the methods described in it, and observing the illustrative examples, it is possible to approach historically the figure of Jesus of Nazareth. This book also serves as an aid and an introduction to the concrete study of the Gospels, so that we have a sufficiently clear notion of its literary and historical value and the reasons for it. It is composed from the strictly historical point of view and from literary criticism, without being subject to any religious confession, but also without practicing any ideological militancy. It is a simple, as far as possible, ordered and (almost) complete presentation of the methods used by historical science to approach the first sources about Jesus.