Like is says on the tin. 101 Variant monsters (44 pages), ordered by CR for Pathfinder.
Takes the normal monster from the Pathfinder Bestiary and provides an alternate or variant version. Perfect to spring a little new life into that standard monster (some of which have their roots in the game going back 30+ years).
Sure you can come up with all of this on your own, but there are lot of clever ideas here and for $6 you get 101 "new" monsters. Not a bad deal at all really.
[5 of 5 Stars!]