(Topics)Assorted topics in recreational mathematics.

(Topics)Biographies of mathematicians (including posters of mathematicians and maps of birthplaces), histories of various mathematical topics, mathematics in various cultures, quotation index, lists of societies and honors, and famous curves index.

(Topics)Volume I: propositional and first-order logic through the Soundness, Completeness, and Compactness Theorems; applications of the Compactness Theorem. Volume II: The basics of computability using Turing machines and recursive functions, plus the Gödel Incompleteness Theorems.

(Topics)Categories, Functors, Naturality, Adjunctions, Duality, Constructions (Iso, Epic, Monic, Initial, Final, Products, Sums, Coequalizers, Colimits)

(Topics)Invariant theory, physics, modular forms, algebraic geometry, string theory.

(Topics)Projective Modules and Vector Bundles, the Grothendieck group, K1 and K2 of a ring, definitions of higher K-theory.