Online Textbooks

Botany Online 
English edition of "Botanik Online" by Peter v. Sengbusch. So far, the first 45 chapters have been translated into English covering all plant anatomy, classic genetics, organic chemistry and plant biochemistry, intercellular communication, interactions between plants, fungi, bacteria, and viruses, evolution, and a part of ecology.

Kimball's Biology Pages
Introductory biology text adapted from print version by Dr. John W. Kimball, retired from Harvard University.

Rediscovering Biology
Online textbook providing content, activities, and resources to help viewers deepen and extend their understanding of new developments in the field of biology.

The Biology Project 
Tutorials and problem sets for studying advanced level biology.

Online Biology Book 
College-level introductory biology by M.J. Farabee.

BioCoach
Review and practice materials on various topics.

Anomalities and Curiosities of Medicine 
Encyclopedic collection of rare and extraordinary cases, of the most striking instances of abnormality in all branches of medicine and surgery, derived from an exhaustive research of medical literature from its origin to the present day (1910's).