It contains 6 self contained stories written by Paul Dini and illustrated by Dustin Nguyen (sp).
Unfortunately, while a certain amount of background into the recent Bat stories is necessary, its still very enjoyable and an easy read for casual readers.
One of the best things about Dini is his grasp of the characters of Bruce, Dick & how they both behave as Batman. Right now I'm reading Private Casebook alongside Streets of Gotham and there is a very subtle difference to the way Dini writes Bruce as Batman & Dick as Batman.