This is perhaps the main treatment of exploitation by a mainstream academic philosopher. The book doesn't focus much on economic or labor exploitation but on things like exploitation of patients by therapists, exploitation of college athletes, etc. When he does treat of economic exploitation, he has some rather abusrd things to say. He confuses coercion with force. Thus a worker who is desperate and takes a job offer isn't coerced by the employer, but nonetheless she could say she was forced to take the job. He says that a person who gets their "reservation price" for something has an equality of bargaining power with the buyer. Reservation price is the lowest price you'd willingly agree to. So if you don't get your reservation price, you were probably coerced. What follows is that if you take a job from some gigantic corporation, you and that corporation have equal bargaining power -- a completely idiotic conclusion.
Nonetheless, the book is worthwhile for its introductory discussion of the elements that make up exploitation. However, i'd skip the book and read his shorter treatment on the website of the Stanford University Encyclopedia of Philosophy. He does have some arguments that seem correct to me -- he argues there can be consensual mutually advantageous exploitation -- in fact this is what the capitalist labor market is.