Science textbooks can be very pricey (as I am sure a lot of you already know.) The National Center for Biotechnology Information (NCBI) at the National Institutes of Health (NIH) has aquired the rights to publish some well-known biomedical text books on-line. The books include:
Berg, Jeremy M.; Tymoczko, John L.; and Stryer, Lubert. New York: W. H. Freeman and Co.; 2002.
Introduction to Genetic Analysis. 7th ed.
Griffiths, Anthony J.F.; Miller, Jeffrey H.; Suzuki, David T.; Lewontin, Richard C.; Gelbart, William M. New York: W. H. Freeman & Co.; c1999.
For a complete list of books, check out the main page of the NCBI Bookshelf.