* Not principally math-related:

The _Economist_ World Atlas and Almanac (1989, hardback)
The Great Barrier Reef (hardback)
The Merck Manual (8th ed., hardback)
Comix Anthology
Say it in Modern Greek
Travesties (Tom Stoppard)
X Protocol Reference Manual
Fluid Concepts and Creative Anthologies (Douglas Hofstadter)
Metamagical Themas (Douglas Hofstadter)
The Mind's I (Hofstadter and Dennett)
Extreme Programming Explained (Kent Beck)
The Human Use of Human Beings (Norbert Wiener)
aha! Insight (Martin Gardner)
Software Tools (Kernighan and Plauger)
The Mythical Man-Month (Fred Brooks)
China Crosses the Yalu (Whiting)
Korean in Plain English (De Mente)
The Tao of Programming (James)

* Mathematics

Groups of Finite Order (Robert D. Carmichael)
A History of Mathematical Notations vol 1 (Florian Cajori)
James & James Mathematics Dictionary (hardback)
Differential Geometry of Curves and Surfaces (hardback; Do Carmo)
Introduction to Automata Theory, Languages, and Computation (1st ed.; hardback; Hopcroft and Ullman)
Nonroutine Problems in Algebra, Geometry, and Trigonometry (damaged; Bryant, Graham, Wiley)
Laws of Form (G. Spencer-Brown)
Topology (hardback, damaged; James Munkres)
The Beauty of Doing Mathematics: Three Public Dialogues (Serge Lang)
Div, Grad, Curl, and All That (Schey)
Classics of Mathematics (ed. Calinger)