The first edition of Adaptive Behavior and Learning was published at a time when research on animal learning was at its apogee. By 1983 the divisions of the field and its basic principles had already been established. Advances have been made since then in mapping neurophysiological underpinnings and in the elaboration and refinement of theoretical models. Many new experimental papers have been published. But relatively little has been added by way of fundamental principles or new behavioral techniques. Even without revision, therefore, AB&L had acquired relatively little of a Rip van Winkle aspect even after thirty years. This impression was confirmed as I continued to receive requests for the book even though it had long been out of print. Cambridge University Press issued a digitally printed edition of the original book in 2009. Hints that the book still had signs of life led me over the years to revise and modify it, leading to the creation of an internet edition in 2003, revised again in 2010.

In 2013, I approached Cambridge with the idea that they might be willing to convert my 2010 PDF file into a Kindle format, so the book could reach a larger audience. They declined, but after some discussion made a counter offer of a new paper edition. I happily agreed. But this new development forced me to reconsider the whole project.

I decided to do a complete revision. The original book had an odd format: relatively elementary chapters, each followed by a more advanced appendix. Citations were named in the text, in the standard style. I have modified both these features in this edition. The research literature on animal learning has grown vast. To cite every author in the text would be otiose – and distracting, encouraging the reader to focus on the names rather than the ideas. So citations are now largely confined to footnotes. The internet, which did not exist at the time of the first edition, now provides ready access to scholarly sources. It makes unnecessary a totally comprehensive reference list. As for the mathematical appendices, only Chapter 4 retains an appendix. Otherwise, I have incorporated that material, plus several new topics, into the chapters, some of which are slightly more mathematical than before.