The CABI website links to the Directory of Open Access Books where you can find downloadable books on various subjects including over 300 on medicine and 350 on social science. The books are not all in English, there are publications in a number of other languages too, and the website itself has English and French versions. Definitely worth a look.
http://www.doabooks.org/doab?func=subject&uiLanguage=en
HIFA profile: Malcolm Brewster is a Community Nurse with the National Health Service, UK