Some of the books in our bookstore (most of the PDF versions of e-books) are Name-Your-Price products. That means that while we set the minimum amount (from $0 to $0.99), the amount you actually pay is up to you. Every dollar you add on top of the minimum price is a charitable donation that will be used to keep B. F. Skinners books in print, convert more works into e-book formats, provide free access to more and more articles, photographs, videos and other archival material through our website.

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The B. F. Skinner Foundation Science and Human Behavior ...