Ward Farnsworth is a law professor at Boston University and author of books and academic articles on a range of subjects. He has released his two volume set of books on tactics online for free under a CC license. The books are available in an interactive format at Chesstactics.org. and hard copies of books are available through Lulu, a print on demand publisher, in two volumes.
From his website:
Before heading to law school I spent some (well… a lot of) time, playing and teaching chess. Portland had several great coffee house where you could hang out and play chess all day. Currently chess is a very closed market. Very few books or applications are under open licenses. Most of the top chess playing programs are closed source and both of the top database programs are closed. I personally spent a lot of money on Chessbase and Fritz. When I would teach children it became clear that the cost of books and programs was a barrier to helping some kids learn to play, especially if their parents did not have a background in chess.
Each section has a simple introduction and all tactical problems have solutions with explanatory text telling readers what is going on and why the solution is correct. He gives very detailed systematic understandable explanations of chess tactics. In addition, when a tactic is not readily apparent, he also explains how to force the opponent into a position that allows you to execute it. This project especially is meant for those who like explanations in words. This site goes into greater detail than other books do in explaining each type of tactic and how to overcome the various obstacles that can arise in trying to make it work.
The site has two parts. The first part teaches chess tactics. The second part allows you to quiz yourself on positions from the book. In the book format there are over 700 pages in total, with more than 1,000 illustrations and commentaries. Link to Site
Ward Farnsworth on Freedom for IP. Freedom for IP is a grass roots organization dedicated to exploring the interaction of Intellectual Property Legislation with Human Rights. Freedom for IP is committed to providing resources, references and news about issues related to Intellectual Property and Human Rights. Freedom for IP is actively engaged in researching and discussing ideas on how to balance conflicting interest of IP and Human rights in an information age.