Freebookcentre.net contains links to thousands of free online technical books. The books collection are either downloadable or can be viewed online. The collections include core Computer Science, Electronics, Science, Medical and many more.
Here is an uncategorized list of online programming books available for free download. The books cover all major programming languages: Ada, Assembly, Basic, C, C#, C++, CGI, JavaScript, Perl, Delphi, Pascal, Haskell, Java, Lisp, PHP, Prolog, Python, Ruby, as well as some other languages, game programming, and software engineering. The books are in various formats for online reading or downloading.
This is a collection of medical books covering several areas of medicine such as Anatomy, Cardiology, Dermatology, Hematology
Infectious Diseases, Neurology, Oncology, Pharmacology and Radiology.
This site lists free online Computer Science, Engineering and Programming books, textbooks and lecture notes, all of which are legally and freely available over the Internet.