I'll be completely honest: This book probably doesn't deserve 4 stars, but it certainly doesn't deserve the 2 stars that the only other review (at this time) gave it, so I wanted to balance things out.
This is a series of 5 short stories, each focussing on a different well-known villain from Gotham, and each opened and closed by Joker himself. Mostly these stories are good quality, and although the frankly terrible Clayface one at the end left a bad taste in my mouth, the other four more than make up for it. The other characters to be featured (besides Joker) are Mad Hatter, Harley Quinn, Riddler and Killer Croc. Normally I don't care for Mad Hatter as a character, and Croc is rarely done justice, but both are done well in this volume. Each story also uses its own art style, which some might find irritating, but I enjoyed, especially getting to see 5 different Jokers and Bats.
Anyway, to wrap up, if you're like me and you find Batman's villains more interesting that the hero himself (or his allies/companions/sidekicks etc) then I'd recommend picking this volume up. However, if you're more interested in stories focussed on Bruce himself, or if you're no major fan of the 5 villains on show, missing Joker's Asylum 2 won't be the end of the world.