Basic Concepts of Mathematics - This text by Elias Zakon helps the student complete the transition from purely manipulative to rigorous mathematics. Chapters cover Set Theory, the Real Numbers, and n-dimensional Geometry.
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.
Dynamics and Chaos - Class notes by Evans M. Harrell II for an introductory course on dynamical systems and chaos, taken by mathematicians, engineers, and physicists. This text concentrates on models rather than proofs in order to bring out the concepts of dynamics and chaos. Theorems are carefully stated, though only occasionally proved.
Geometric Constraint Solving - An electronic primer by William Bouma, Xiangping Chen, Ioannis Fudos, Christoph Hoffmann, and Pamela J. Vermeer.
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.
Harmonic Analysis and Partial Differential Equations - A book by Dahlberg and Kenig in postscript (bitmapped fonts). The page also contains another book by Dahlberg: "Icke Linjära Evolutionsekvationer" (Swedish).
Homeomorphisms in Analysis - A survey by C. Goffman, T. Nishiura, D. Waterman in PDF. In particular, the effects of homeomorphic changes of domain on the analyticity of a function are studied.
Lecture notes by László Lovász - Discrete mathematics topics in Postscript. Includes "Discrete Mathematics", "Semidefinite optimization", "Topological methods in combinatorics", and "Complexity of algorithms".
Lecture Notes on Optimization - By Pravin Varaiya. This book is an introduction to mathematical programming, optimal control, and dynamic programming. [PDF]
The Limits of Mathematics - An online course on information theory and the limits of formal reasoning by G.J. Chaitin.
Linear Methods of Applied Mathematics - Textbook suitable for a first course on partial differential equations, Fourier series and special functions, and integral equations by Evans M. Harrell II and James V. Herod. HTML, RTF and PDF with Maple and Mathematica worksheets.
Linear Partial Differential Equations and Fourier Theory - Complete textbook by Marcus Pivato on the solutions of linear partial differential equations, with emphasis on eigenfunction methods (and hence, Fourier analysis). Lots of pictures. [PDF]
Math Wizard - E-book gives some ideas on alternative approaches to teaching and learning math. Page includes table of contents. Requires a purchase.
Mathematical Illustrations - A manual of geometry and PostScript by Bill Casselman, including code samples and packages.
Mathematical Methods of Engineering Analysis - Book by Erhan Çinlar and Robert J. Vanderbei. Topics covered: functions on metric spaces, differential and integral equations, convex analysis, and measure and integration. [PDF]
Meta Math! The Quest for Omega - A mathematical and philosophical book by Gregory Chaitin on logic, information theory, complexity, etc. (available in html or pdf).
Numerical Grid Generation - A book by Thompson, Warsi, and Mastin, previously published by Elsevier, in HTML.
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.
Numerics - Interactive - In this book by Thomas Risse, basic numerical algorithms are presented and implemented in order to determine the precision of computation, to solve systems of linear equations, to evaluate elementary functions, to find zeros, to integrate and to solve ordinary differential equations numerically. The performance of different algorithms can be compared. [PDF]
Plane Geometry - Shalosh B. Ekhad XIV. A fully illustrated and completely self-contained Elementary Geometry textbook (ca. 2050), downloaded from the future by Doron Zeilberger. Entirely written in Maple.
Potential Theory - Two texts by V.I. Fabrikant: Applications of Potential Theory in Mechanics, Selection of New Results (1989); Mixed Boundary Value Problems of Potential Theory and their Applications in Engineering (1991). Text in PDF with figures separately in JPG.
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.
Several complex variables - Several sets of lecture notes by Jean-Pierre Demailly, some in French, including "Potential theory in several complex variables", and "Multiplier ideal sheaves and analytic methods in algebraic geometry" in DVI or PostScript.
Sheaf Cohomology - Mathematical notes on sheaves and other topics by P. Morandi.
Splines and Wavelets - A monograph by Karl Scherer in German (DVI and Postscript).
Stochastic Calculus - A fairly complete elementary introduction to the basics of stochastic integration with respect to continuous semimartingales by Alan Bain. All the theory usually needed for basic mathematical finance. Sixty pages in 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
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.
Voting, Arbitration & Fair Division: Mathematics of Social Choice - An introduction to `social choice theory', which uses mathematics to study the strengths/weaknesses of voting systems, arbitration schemes, and other methods of group decision making. Lots of pictures, requires only basic linear algebra. Author: Marcus Pivato. [PDF]