Algebraic Topology - Basic core material along with a number of optional topics of a relatively elementary nature by Allen Hatcher. PDF and Postscript.

Generatingfunctionology - By Herbert S. Wilf. Published by Academic Press. PDF.

Euclid's Elements - Edited by D.E. Joyce. HTML text with Java applets.

Fundamentals of Model Theory - Introductory textbook by William Weiss and Cherie D'Mello. PostScript, DVI, GIF.

Probability - "Introduction to Probability" by Charles M. Grinstead and J. Laurie Snell in PDF. Published by the AMS. The site also contains additional teaching resources.

A=B - Combinatorics text by Marko Petkovsek, Herbert Wilf and Doron Zeilberger. Published by A. K. Peters. PDF.

Abstract Algebra: The Basic Graduate Year - By Robert B. Ash. Chapters in PDF.

Numerical Recipes Books On-Line - The complete Numerical Recipes books in C, Fortran 77, and Fortran 90 On-Line, in both PostScript and Adobe Acrobat formats.

Algorithms and Complexity - By Herbert S. Wilf. In print 1986-1994. Single PDF file.

Mixed Motives - Monograph by Marc Levine published by AMS in 1998. Whole book or chapters in PDF.

Tensor Calculus and Continuum Mechanics - Textbook by John H. Heinbockel. Whole book or chapters in PostScript and PDF.

Practical Foundations of Mathematics - An account of the foundations of mathematics (algebra) and theoretical computer science, from a modern constructive viewpoint by Paul Taylor. Published by Cambridge University Press. HTML approximation.

Elements of Abstract and Linear Algebra - Foundational textbook on abstract algebra with emphasis on linear algebra by Edwin H. Connell. Whole book or chapters in DVI, PostScript, and PDF.

Complex Analysis - Textbook for an introductory course in complex analysis by George Cain. Chapters in PDF.

Universal Algebra - "A Course in Universal Algebra" by Stanley Burris and H. P. Sankappanavar. PostScript and PDF.

C*-Algebras - "An Introduction to C*-Algebras" by Pierre de la Harpe and Vaughan Jones. The site is in French, but the book is in English. Chapters in PostScript.

Probability Theory: The Logic Of Science - Probability theory viewed in a wider context by Edwin Jaynes in PostScript and PDF based on the author's lectures at Stanford Univ.

Index Theory, Geometric Scattering, and Differential analysis on manifolds with corners - Several books by Richard Melrose et al. in PostScript.

Linear Algebra - Textbook by Jim Hefferon covering the material of any undergraduate first linear algebra course. Book or chapters in PDF.

Abstract Algebra - Lecture notes by David Wilkins from a course at Trinity College, Dublin. Three parts in DVI, PostScript and PDF.

Templates for the Solution of Linear Systems - Book on iterative methods by Richard Barrett et al. in HTML and Postscript.

Semi-Simple Lie Algebras and their Representations - Book for particle physicists by Robert N. Cahn. Published by Benjamin-Cummings in 1984. Chapters in PostScript.

Abstract Algebra II - A companion volume to "Abstract Algebra" by John A. Beachy and Bill Blair published by Waveland Press in 1995. Chapters in PostScript.

Linearization via the Lie Derivative - By Carmen Chicone and Richard Swanson. LaTeX, DVI, PostScript and PDF.

Multivariable Calculus - Textbook by George Cain and James Herod. Chapters in PDF.

Topology Without Tears - A course in topology by Sidney A. Morris in HTML with embedded GIFs. Some chapters available in PostScript.

Finite Rank Torsion Free Modules Over Dedekind Domains - Monograph in commutative ring theory by Lee Lady. DVI and PDF.

Measure Theory and Integration - Lecture notes by Vitali Liskevich in DVI from a course taught at the Univ. of Bristol.

Topology Course Lecture Notes - By Aisling McCluskey and Brian McMaster. HTML with symbol fonts, DVI and PostScript.

Trigonometry - "Dave's Short Trig Course" by D. E. Joyce. HTML with Java.

Analysis WebNotes - Online course by John Lindsay Orr. Chapters also available in LaTeX.

Advanced Calculus and Analysis - Lecture notes by Ian Craw from a course at the Univ. of Aberdeen. HTML with GIFs.

Interactive Real Analysis - "Interactive Real Analysis" by Bert G. Wachsmuth. HTML and Java.

Complex and Functional Analysis - Lecture notes by Douglas N. Arnold for a course at Penn State. Two parts in TeX, DVI, PostScript and PDF.

Category Theory - "A Gentle Introduction to Category Theory - the calculational approach" by Maarten M. Fokkinga in PostScript.

Multiplier Ideals for Algebraic Geometers - Draft of a part of a book in preparation on positivity in algebraic geometry by Robert Lazarsfeld. DVI and PostScript.

Dynamical Systems - 1927 classic by George D. Birkhoff published by AMS. Scanned chapters in PDF.

Complex analytic and algebraic geometry - Book by Jean-Pierre Demailly in PostScript.

Physics, Invariant Theory, Modular Forms, and Algebraic Geometry - Several lecture note sets by Igor Dolgachev in various formats, including DVI and PostScript.

Differential Geometry - Notes by Balázs Csikós. Chapters in PostScript.

Finite Element Method/Boundary Element Method - Notes by Peter Hunter and Andrew Pullan. Postscript and PDF.

Functional Analysis and Semi-Groups - Book by Einar Hille and Ralph S. Phillips published by AMS in 1957. Scanned chapters in PDF.

Global Analysis - "The Convenient Setting of Global Analysis" - foundations of differential calculus in infinite dimensions with applications to differential geometry and global analysis by Andreas Kriegl and Peter W. Michor published by AMS in 1997. Whole book or chapters in crosslinked PDF.

Complex Dynamics in Higher Dimensions - CBMS lecture notes by John Erik Fornæss at the bottom of page with other papers by the author and Nessim Sibony. PostScript.

Several complex variables - Several sets of lecture notes by Jean-Pierre Demailly, some in French, including "Potential theory in several complex variables", "Multiplier ideal sheaves and analytic methods in algebraic geometry", etc. in DVI or PostScript.

Algebraic Topology - 1942 classic by Solomon Lefschetz published by AMS. Chapters in scanned PDF.

Travelling Wave Solutions of Parabolic Systems - Translation of a monograph by Aizik Volpert, Vitaly Volpert, and Vladimir Volpert published by AMS in 1994. Whole book or chapters in PDF.

Invariance Theory, the Heat Equation, and the Atiyah-Singer Index Theorem - Monograph by Peter B. Gilkey published by Publish or Perish and CRC Press. Whole book or chapters in DVI and Postscript.

Matroid Decomposition - Monograph by Klaus Truemper published by Academic Press in 1992. Chapters in PostScript.

Spinors, Spectral Geometry, and Riemannian Submersions - Monograph by Peter B. Gilkey, John V. Leahy and Jeonghyeong Park published by Seoul National University in 1998. DVI and PostScript.

Differential Geometry - "Natural operations in differential geometry" by Ivan Kolar, Jan Slovak and Peter W. Michor published by Springer-Verlag in 1993. DVI, PostScript and PDF.

Theory of Symmetry and Ornament - Monograph by Slavik V. Jablan published by the Serbian Academy of Science and Arts in 1995. HTML

Complex-Analytic Geometry of Complex Parallelizable Manifolds - Monograph by Jörg Winkelmann. Chapters in DVI.

Differential Geometry - Several books by Peter W. Michor et al. including "Foundations of Differential Geometry", "Natural operations in differential geometry" (corrected version), "Transformation Groups", "Gauge theory for fiber bundles" etc. plus many papers by the author in postscript.

Computational Geometry and Computational Optimization - Lecture notes by Jianer Chen in PostScript.

Differential Topology - Course notes by Matthew G. Brin in PostScript including "Introduction to Differential Topology", "Introduction to Seifert fibered 3-manifolds", "Groups acting on 1-dimensional spaces", and "Presentations, conjugacy, roots and centralizers in groups of piecewise linear homeomorphisms of the real line".

History of Calculus - Guide To History of Calculus. Topic essays and biographies keyed to the chapters and content of the 10th edition of Thomas's Calculus.

Differential Geometry - Lecture notes for an honors course at the University of Adelaide by Michael Murray in HTML with GIFs.

Differential Geometry - Lecture notes for a course at the Weizmann Institute of Science by Sergei Yakovenko. Chapters in DVI.

Manifolds, Tensors, Analysis, and Applications - Book by R. Abraham, J. E. Marsden, and T. Ratiu originally published by Addison-Wesley in 1983. Chapters in PDF.

Linear Programming: Foundations and Extensions - Book by Robert J. Vanderbei in PDF.

Mathematical Methods of Engineering Analysis - Book by Erhan Çinlar and Robert J. Vanderbei in PDF. Topics covered: functions on metric spaces, differential and integral equations, convex analysis, and measure and integration.

Linear Algebra - "Elementary Linear Algebra" by Keith Matthews. Lecture notes and solutions from 1991 in PDF or PostScript.

Numerical Analysis - "Introduction to Numerical Analysis Using Maple" by Barry G. Adams in HTML.

Dynamical Systems and Fractals - Lecture Notes by David J. Wright in HTML.

Mathematical Modeling in a Real and Complex World - Online guide book by Frank Wattenberg in HTML.

Entropy of Compact Group Automorphisms - Lecture notes based on a course at Ohio State in 1994 by Thomas Ward in DVI and PostScript.

Geometric Constraint Solving - An electronic primer by William Bouma, Xiangping Chen, Ioannis Fudos, Christoph Hoffmann, and Pamela J. Vermeer.

Geometry and the Imagination - An online course by John Conway, Peter Doyle, Jane Gilman and Bill Thurston in HTML and PostScript.

Fundamental Problems in Algorithmic Algebra - Book by Chee Yap published by Oxford University Press in 1999.

Wavelet Tutorial - Guide to wavelet analysis by Robi Polikar.

Discrete Mathematics - Lecture notes by László Lovász in Postscipt. Includes "Discrete Mathematics", "Semidefinite optimization", "Topological methods in combinatorics", and "Complexity of algorithms".

Abstract Algebra - Course notes by J.S. Milne in DVI, PostScript and PDF including "Group Theory", "Fields and Galois Theory", "Algebraic Number Theory", "Class Field Theory", "Modular Functions and Modular Forms", "Elliptic Curves", "Algebraic Geometry", "Lectures on Etale Cohomology", and "Abelian Varieties".

Abstract Algebra - "Intro to Abstract Algebra" by Paul Garrett in PostScript and PDF.

The FEMCI Book - Finite Element Modeling Continuous Improvement. A web text by Ryan Simmons.

Algebraic Topology: A Computational Approach - Book by T. Kaczynski, K. Mischaikow, and M. Mrozek in PostScript.

Algebraic K-theory - "An introduction to algebraic K-theory" by Charles Weibel. Chapters in DVI.

Complex Analysis - Course notes by Harold V. McIntosh in HTML.

Dynamics in One Complex Variable: Introductory Lectures - Lecture notes by John Milnor in TeX and PostScript.

Mathematical Logic - "A Problem Course in Mathematical Logic" by Stefan Bilaniuk in LaTeX, PostScript or PDF.

Linear Algebra and Applications - Textbook by Thomas Shores. GIFs of pages.

Mathematical Principles of Natural Philosophy - Principia by Isaac Newton (1687) translated by Andrew Motte (1729) in HTML (incomplete).

The Limits of Mathematics - An online course on information theory and the limits of formal reasoning by G.J. Chaitin.

Hilbert Space Methods for Partial Differential Equations - Textbook for beginning graduate students of mathematics, engineering, and the physical sciences by Ralph Showalter. Chapters in PostScript and PDF.

Flatland - A romance of many dimensions. With Illustrations by the Author, A SQUARE (Edwin A. Abbott 1838-1926). HTML.

Plane Geometry - Shalosh B. Ekhad XIV. A fully illustrated and completely self-contained Elementary Geomtry textbook (ca. 2050), downloaded from the future by Doron Zeilberger. Entirely written in Maple.

Differential Geometry and General Relativity - Introduction to differential geometry and general relativity by Stefan Waner at Hofstra University in HTML.

Algebraic Combinatorics via Finite Group Actions - HTML book by A. Betten, H. Fripertinger, and A. Kerber.