Should there not be an autobiography genre, as well as biography, instead of having to use non-fiction.

I'm only a librarian small scale but Autobiography and Biography are kept separate but close in my library.

the difference between autobiography and biography is that an autobiography is the authors' own life story. A biography is the authors' story of the life of someone else. That's the reason I think there should be separate categories.

Does a Haynes manual count as an Autobiography?

One can write a biography of any one. For example, you could today write a biography of some historical figure. It is only an autobiography when it it written by the subject herself/ himself.

One needs go back to the greek and latin roots of the words

bio = life (greek bios)
graphy = writing (greek graphia)
auto = self (latin autos)

therefore a biography is a life-writing and an autobiography is a self-life-writing

both are the same - just depends on who wrote 'em

Amy