Free Math Textbooks

These are books that i've verified them in one way or another. Some i've read and consider good, some i checked up the author and is reputable mathematician, some are well known professors i know of, etc.

Number Theory

• Elementary Number Theory by W Edwin Clark (highschool readable)
• A Computational Introduction to Number Theory and Algebra , by Victor Shoup (not verified)

Calculus

• Free Calculus Textbooks

Linear Algebra

• Linear Algebra, by David Cherney and Others
• Linear Algebra, by Jim Hefferon

Real Analysis

• Real Analysis by Jiri Lebl 2016

Complex Analysis

• 
  Visual Complex Analysis by Tristan Needham

Differential Geometry

• Lecture Note on Curves and Surfaces, 2005, Chuu-Lian Terng (undergrad)

• A Modern Course on Curves and Surfaces, 2003, by Richard S Palais (undergrad)

• Functional Geometry, 2013, Sussman, Wisdom, Farr (undergrad)

• Analysis on Manifolds, 1991, by J R Munkres

Topology

• Intro to Point-Set Topology by Allen Hatcher

• Topology from the Differential Point of View, 1965, John W Milnor

Logic

• A Course In Universal Algebra, Burris, Sankappanavar

• Mathematical Logic, by Stephen G Simpson (graduate)

• Introduction to Proof Theory, 1998, by Samuel R Buss (graduate)

• Foundation of Math, by Stephen G Simpson (graduate)

• Homotopy Type Theory
• (graduate)

Infomation Theory

• Information Theory, Inference, and Learning Algorithms by David J C MacKay

Category Theory

• Category Theory, by Tom Leinster

not verified

the following i have not verified.

• ALGEBRAIC CURVES, An Introduction to Algebraic Geometry, by William Fulton

• Intro to Topology by Renzo