Below you can find a list of math books which are free to download. Some of them I know are available on the internet after negotiations between the authors and the publishers. So, here I’d like to thank the authors for all their work writing theses books and also for their fight in favor of democratic access to knowledge!
Probability
Elementary Probability for Applications
by R. Durrett
Random Graph Dynamics
by R. Durrett
Statistical Mechanics of Lattice Systems: A Concrete Mathematical Introduction
by S. Friedli and Y. Velenik
Probability and Statistics: The Science of Uncertainty
by M. Evans and J. Rosenthal
Random Graphs and Complex Networks: Volume 1
by R. van der Hofstad
Brownian Motion
by P. Mörters and Y. Peres
Markov Chains and Mixing Times
by D. A. Levin and Y. Peres
Probability on Trees and Networks
by R. Lyons and Y. Peres
Probability: Theory and Examples
by Rick Durrett
Random Matrices
An Introduction to Random Matrices
by G. Anderson, A. Guion, O. Zeitouni
Indicate a free book
Rodrigo Ribeiro 