Softcover book is in excellent condition.
This fun little tome is a GM utility for use during regular play when either too many good things happen to the players due to luck or just whenever the GM feels they need a little push to remind them that success is fleeting.
Dirty tricks are intended to create great players. That is and should be the only reason a GM springs such things on them. It also has the effect of creating a great game, where even mundane tasks cannot be taken for granted, and boredom is rare.