Any examination into the life and works of Jesus that wishes to advance beyond the basic declaration that he was a historical figure who lived in first century Palestine must deal centrally with the gospels. This is not to say, of course, that scholars who attempt to reconstruct what we can know about Jesus simply look at the gospels and guess which parts are accurate. Far from it. They use techniques and research from a number of difference fields (archaeology, anthropology, sociology, classics, literary theory, etc), and a number of other texts (Old Testament texts, intertestamental literature, rabbinic literature, classical literature, epistles, early Christian writings apart from the gospels, apocryphal gospels, etc), in order to help them understand an analyze the gospels on both a macro and micro level. However, at the center of all this is almost always the four gospels represented in the New Testament.
The first step in dealing with the gospels is to determine their genre. When I use the word genre here, I am using it in a slightly wider sense than it is normally used (e.g. the genres in Borders or Barnes and Nobles). For one thing, I am applying the term to cover a much wider range of material, not just books (epigraphs on grave stones, for example, are a particular type of genre). For another, I am applying it not only to written material but to oral. For example, jokes are a type of oral genre, as are political speeches.
Genre, among other things, determines not only the particular style of a text (oral or written), but also its purpose. Let me use an example to help clarify: eulogies. Eulogies are a particular type of oral genre. This genre determines not only the general style of the speech, but also its purpose. In general, the style consists of fond memories, talking about the noble aspects or good qualities of the dearly departed, and so on. The purpose is to honor the deceased, share personal grief with others, and make sure that the deceased lives on in our memories. As such, this particular genre determines what types of material are admitted into such a speech. The descriptions of the deceased are supposed to be accurate (more or less) but they are often exaggerated. Negative qualities, unless they are amusing or quirky and very minor, are never brought into a proper eulogy. So while a eulogy may give us a sense of the deceased, the genre filters out a great deal of material, and what is admitted must be presented in a particular fashion.
To understand any text, not just the gospels, knowing the genre is vital. If you dont know the genre, you cant tell the general purpose behind the work, why certain types of material is admitted and other types are not, why the material is presented in a certain way, etc. Of course, in any genre, innovation occurs, and some works are difficult to place (this is particular true today, when innovation is so sought after by artists).
When it comes to the gospels, determining genre allows us to begin to analyze the texts. For example, many of those who argue that Jesus never existed believe the gospels are myths, like those of Osiris, Attis, Mithras, Hercules, etc. I can state from the outset that this is not at all true. The gospels are quite different from the genre of classical myth.
I dont have to go into excruciating detail to demonstrate this (although it has been done). A simple point can illustrate successfully a distinct difference. Myths (of the types mentioned above) always occur in bygone days, far, far removed from the time of the account. Even in the oldest of Greek literature, the epics of Homer, the events described are already of an age passed. All the myths, from Jason and Medea, to Kore and Hades, etc, all take place in ages and places (some fantastical) far removed from the time they myth is being told. This is important, because it allows them to be unverifiable. It is also important to note that in any given myth versions would multiply like rabbits, and this was perfectly acceptable. Even central themes would change (for example, did Medea kill her own children, or was it the Corinthians? If it was medea, did she do it for revenge, or in an attempt to make them immortal?). The Greeks and Romans would often be familiar with several versions of any given myth, and the contradictions never presented a problem.
Not so with the gospels. Unlike the myths, the gospels are nailed down to a particular time and place, within a few decades of their composition. This is unheard of in myth. Likewise, parts of the gospels, for example many of the people mentioned, are confirmed independently of the gospels (John the Baptist and Caiaphas the high priest in Josephus, Pilate from archaeology and Philo among others, Herod, etc). The gospels, then, clearly do not fall into the genre of myth.
So what genre are the gospels? In a sense, the gospel genre is gospel. There isnt anything EXACTLY like them. However, there is another type of ancient genre that the gospels could fall into, and if they dont match it exactly, they are fairly close. The gospels are a type of ancient biography known as a life (bio/vita). As such, they are also a type of ancient history.
Now I know that anyone who has read the gospels may object to my last statement. Clearly the gospels cant be history, because they contain miracles, theology, inaccuracies, etc, right? Well, they certainly cant be considered history by modern standards. However, ancient standards were different. Although historians in general sought to record the truth, their standards of proof were much lower. Much of ancient history contained miracles, theology, rumor, speculation, magic, myth, etc. To demonstrate a little more clearly, I will use Herodotus as an example, both because he is considered the first of the Greco-Roman historians, and because I can quote from a paper I have already written (yes, I am that lazy). I apologize if the style is a little more formal: