The Q source or Document Q is a supposedly lost source that is believed to be the origin of the elements common to the Gospels of Matthew, Mark and Luke. According to historians, it is a compilation of the sayings of Jesus of Nazareth, dating from around the year 50. The Q source hypothesis is a direct consequence of the two-source theory. This theory says that the Gospel of Mark and the Q source served as the source for the writing of the Gospel of Matthew and Luke. In this book, I present the arguments that prove that this compilation of Jesus' words is authentic and that it is what historians call the Q source. This work also includes a historical and philosophical biography of Jesus as well as a narration of the events that followed (Apostolic Era). Finally you will find a commentary section on the sayings of Jesus. To conclude this description, some people would ask, what is the use of knowing the original words of Jesus if the churches fathers have decided to hide it and to favor the gospels versions ? It is an understandable opinion but fom of philosophical point of view, how can we know the end of the road if we do not know the starting point ? Without the hindsight that comes from knowing the origin, how can you find the way out of this maze ?