A Wikipedia search (http://en.wikipedia.org/wiki/Cape_Cod_Baseball_League) of the Cape League will reveal 4 fine histories of the CCBL. The open source encyclopedia won't tell you much about the books and film but it does provide a nice basic overview. (I have little comment on the 2001 Hollywood film, Summer Catch -- http://summercatch.warnerbros.com/flash.html) The 4 serious works are:
-Baseball by the Beach, written by Christopher Prise, was published in 1998. http://www.alibris.com/search/search.cfm?S=R&qwork=576965&qsort=p&siteID=Pw2LQAj_zJk-Gv1TQFUg3Drbdj5fK5eLfw
-The Last Best League (2004) is written by Jim Collins and is the only critical, journalistic treatment of the league. It is a must for any fan. http://www.powells.com/cgi-bin/biblio?isbn=0738209015
-Touching the Game is an excellent -- if indulgent -- homage to the CCBL. Produced, written and edited by Jim Carroll, it provides interviews with MBL players who got their starts on the Cape. http://www.touchingthegame.com/
-Beach Chairs and Baseball Bats was published in 2005. I met (and purchased an autographed copy of the book) the author, Steve Weissman, at a Wareham Gateman game during the 2006 playoffs. http://www.amazon.com/Beach-Chairs-Baseball/dp/1419605089
As you would expect from the editor of a blog dedicated to the CCBL, I recommend them all. If you want just one definitive story, I would buy The Last Best League. Collins follows the Chatham As for the entirety of the 2002 season. A former editor of Yankee, Collins is a skilled writer who knows something about character development. We follow management, host families, players, parents and scouts throughout the summer season. The humor is wonderful -- the Chatham parade and the banter in the bullpen. Collins also sniffs out possible steroid use, racial issues and the intricacies of NCAA players negotiating contracts with professional baseball. Baseball by the Beach is a historian's history of the league. It is the Cooperstown edition of the CCBL. I just loved it. You will find that the history of "the Massachusetts game" closely mirrors and shapes that of American baseball.
Beach Chairs is a great reference guide and fan's companion to the league. Steve has ground background on the teams and stadiums and helps to bring the league to life with loads of photos.
All 4 will take up about 4-5 inches on your bookshelf so I recommend them all. And I invite your own comments.