Alexandre Stefanov has long maintained a list of online math texts and other materials at Geocities; this material has now been moved to 110MB Hosting. Because these resources may be of interest to our readers, we present here a modified version of Stefanov's list as of November 18, 2009.

General Topology

• Topology Course Lecture Notes, by Aisling McCluskey and Brian McMaster
• Topology lecture notes (3rd year), by Thomas Ward
• Foliations and the topology of 3-manifolds, by Danny Calegari

Algebraic Topology

• Allen Hatcher's homepage, has a (nearly complete) textbook.
• Introduction to Sheaf Theory and Algebraic Topology, by Pierre Schapira
• Cohomology, Connections, Curvature and Characteristic Classes, by David Mond
• Introduction to Characteristic Classes and Index Theory, by Jean-Pierre Schneiders
• Abstract group theory and topology articles, by Walter Neumann

K-Theory

• An introduction to algebraic K-theory, by Charles Weibel.

Knots

• Knots Knotes., by J. D. Roberts
• Vassiliev invariants and combinatorial structures, by S. V. Duzhin
• Introduction to Vassiliev knot invariants, by S. Chmutov, S. Duzhin
• Collection: History of Knot Theory, by Andrew Ranicki
• Lecture Notes On Knot Theory, by Swatee Naik
• Knot theory from Vandermonde to Jones, by Jozef H. Przytycki