Fortunately, it's pretty obvious Batman: Year One comes first.
Year One is a four part series written by Frank Miller. According to the introduction in the trade paperback, DC wanted to reboot some of their major characters, but felt Batman's origins were still pretty relevant. Frank Miller (famous for Sin City, 300, The Dark Knight Returns) volunteered to write a gritty retelling of Batman's origins.
|Screenshot from the animated movie of the same name.|
The story actually revolves around Commissioner Gordon more than Bruce Wayne. This is not a problem though, the story is absolutely fantastic and seems very real.
This story also had a huge impact on "Batman Begins". A few scenes are taken pretty much directly from the story.
Where It Belongs
There's not a ton of logic to this one, I mean "year one" is in the title. It would say it's same to assume this book is the beginning of the Batman series in graphic novels. Obviously there were years and years of comic books that were released before this, but this is the first one of my (and probably everyone else's) chronological order.