Endnotes.

The reception of the book by my five distinguished colleagues was generally positive, for which I am grateful. There was, however, very little reference, positive or negative, to the specific contents of the book. The commentaries were not in any detailed sense "book reviews," nor, perhaps, were they meant to be. It was more that the commentators, each having done some work on rewardschedule effects-on alternative or related treatments of reward and nonreward (reinforcement and nonreinforcement)--chose to compare and contrast the principles that guide their research with those that guide mine. As I see it, my task in responding is not to deal with each and every point raised by my five colleagues, but to select from among them issues that have some general importance or that raise interesting questions. I would add that, had the book we are discussing been more a textbook on reward-schedule effects and less a monograph based on a particular theoretical approach to these effects, much of the material in the commentaries of my five colleagues would have been included.