book3-copyContingencies of Reinforcement in e-book format is now available not only in the B. F. Skinner Foundation Bookstore, but also through all major online retailers. Here are the clickable links: Amazon, Barnes and Noble, Google Play, iTunes, and Kobo. As always, if you are planning to buy (or purchased already) a print edition of Contingencies of Reinforcement  through Amazon, the Kindle Edition is only $2.99.