You should know about hardware and what types do what, DirectX and a group of people to test. That''s all I have and my game scome out just fine. The good thing about DirectX is... is that you don''t have to learn all that much to come out with something good.

Yes, it is very possible for a single person to develop a game engine...but don''t expect to be makeing FPS/RTS/RPG engines right off the bat....a good single programmer could do just about anything...only it would take much longer then it would with a team of programmers (but this has disadvantages too)....

It is more important to know and understand the core programing concepts then it is the specifics...leave the specifics to resource books (and build a library to house them...its better to know how to understand what you read in a variety of books, then it is to memorize the text of one book)....technology changes all the time...but the core concepts don''t...understand them and you can adapt to the rest.