I enjoyed Dublanica's first book, Waiter Rant, so I picked up this one in hardcover when Borders went bankrupt. Still I wasn't terribly enthusiastic about reading it. An entire book about tipping didn't sound all that interesting.
My concern was unfounded; Keep the Change is surprisingly entertaining. Dublanica doesn't just tell us how much to tip. He actually performs many of the jobs to determine just how much skill is involved and explain why that occupation warrants a tip in the first place. He interviews lots of service workers and learns which jobs rely on tips for compensation. Although concierges appreciate tips, they make more money from the businesses they refer people to. At the other end of the spectrum, one shoeshine explains that when you pay him the $7 fee for a shine, he only gets to keep $1. Since his employer doesn't pay a base wage, tips provide almost all of his pay.
Perhaps the ultimate tipping environment is strip clubs. Writing off his expenses as "research" (in Las Vegas, naturally), Dublanica explains how a $200 half-hour VIP room dance costs nearly $300. There is a two-drink minimum and the drinks are $15 each. Then you have to tip the cocktail waitress 20%, the bouncer $20, and of course the dancer 20%. If you use a credit card, the house takes 10% from the dancer and her tip, so you should tip extra to make up for it. Additionally, one must tip the host to get a good seat. Then he looks at the other side -- how the dancers have to tip the hosts, the house moms, the bouncers, the waitresses, and the DJ. In short, there's money being passed around everywhere.
This book is also full of interesting tidbits. For example, Dublanica tells why manicures cost much less today than they did in the 1970s (you can thank Tippi Hedron!).