Here are some sites that you can buy the book: the first site seems the cheaper
http://www.thameshudson.co.uk/books/Tracing_Eisenman/9780500342251.mxs/15/0/
http://www.dealtime.com/xPC-Book_Tracing_Eisenman_The_Complete_Work_of_Peter_Eisenman_editor_Cynthia_Davidson~r-1~CLT-INTR~RFR-www.google.com (7 offers 40-60 USD)
http://www.amazon.com/Tracing-Eisenman-Complete-Greg-Lynn/dp/0847828891 starting 43 USD