Open Source

Open policy finder

Find out publishers' copyright policies.

Free books from generous authors.

Biology

An Owner's Guide to the Human Genome: an introduction to human population genetics, variation and disease by Jonathan Pritchard

English usage

Common Errors in English Usage

Philosophy/Classics

Digital Library of Darshan Manisha (Texts on Indian Philosophy)

Open Greek and Latin Perseus Digital Library

Physics

Online course on topology in condensed matter

Feynman lectures

Electrodynamics by Phil Nelson (excellent!)

Understanding the Properties of Matter by Michael de Podesta

Entropy by John Baez

Group Theory in Physics: An Introduction with Mathematica by Balasubramanian Ananthanarayan, Souradeep Das, Amitabha Lahiri, Suhas Sheikh, Sarthak Talukdar

Lecture notes on Statistical Physics by Lydéric Bocquet

Lecture notes on Soft Matter and Interfaces by Lydéric Bocquet

Machine Learning

Interpretable Machine Learning by Christoph Molnar

Deep Learning for Molecules and Materials by Andrew D. White

Information Theory, Inference, and Learning Algorithms by David MacKay

The Elements of Statistical Learning by Trevor Hastie, Robert Tibshirani, Jerome Friedman

An Introduction to Statistical Learning by Gareth James, Daniela Witten, Trevor Hastie, Robert Tibshirani

Model-Based Machine Learning by John Winn

The Little Book of Deep Learning by François Fleuret. He formatted the book for reading on smartphones—such innovative people!