Steve Guy
The original story was just Batman 608-619. They made a sequel by different people a couple years later called Hush Returns, but most people agree that its horrible and should be skipped. 5 years later they made a few more stories, Heart of Hush, Hush Money and House of Hush, which were all collected in the recent Batman by Paul Dini omnibus.
Anonymous
27 - 4 - 12 - and after that, they lost count themselves.