This is a really insightful book, a philosophical examination of the morality of incentives. Is it moral, in other words, to dangle a carrot in front of someone in order to get them to do what they might not otherwise. Grant's thoughtful and pluralistic analysis is that one's answer basically depends on three major (and several minor) questions.
Is the purpose of the incentive moral (are we getting someone to be healthy or kill someone)?
Is what we are offering as an incentive moral (are we offering a gift certificate or crack cocaine)?
Is the incentive such that it might change the character of the target (are we "crowding out" potential internal motivation with external motivation)?
There are some other questions the author entertains as relevant (how likely is it that the target wouldn't do x via some other motivation, like reasoning with them?), but these are the "big three." Needless to say, anyone looking for a philosophical argument that simply celebrates or repudiates all incentive structures will be disappointed.
From here, the author gives us four examples of controversial incentive programs and analyzes them using the questions she fleshed out: the use of plea bargains, paying for participation in medical research, a condition of austerity policies placed getting an IMF loan, and paying kids for good school performance. (I really question whether the third of these belongs here, as the IMF loan is not an incentive to get nations to adopt austerity policies, but a condition placed on a loan that countries are already applying for.) I won't rehash the author's positions on all four, but the interesting case to me was that of plea bargaining. Grant expresses aversion (I think, correctly) largely because dangling a lower sentence in front of criminals who plead guilty takes away the "justice" from justice by way of allowing someone to be punished LESS than they would have been for a crime by virtue of saving the state the burden of a trial. Another interesting case was that of paying medical research subjects, which Grant is largely (with limits) for, because all "big three" questions can largely be answered in a way that satisfies moral demands (the first two, "yes," the third, "not likely.")
EE
All in all, a really enjoyable book that will probably change the way (deepen, really) you think about incentives and the moral issues involved with them. I have some quibbles (the author's use of the term "coercion" is probably looser than I think sensible, the author often talks about our intrinsic motivation for doing things without recognizing that some examples she uses - doing well in school - often involve more extrinsic motivations [making parents happy, promise of a high paying job later on, etc] whether incentives are EXPLICITLY used or not). But Grant does philosophy very well, delving very ably into the moral nuances of incentive use.