1) "The Science of Programming", by David Gries, is an excellent book dealing with mathematical proof based approach to programming. 2) "The Book of Numbers",

1) "The Science of Programming", by David Gries, is an excellent book dealing with mathematical proof based approach to programming. 2) "The Book of Numbers", by John H. Conway and Richard Guy is a beautiful book which discusses about figurative numbers amoung several other beautiful topics. 3) "Stories About Maxima and Minima", V. M. Tikhomirov has some beautiful anecdotes and interesting applications of calculus. 4) "Contemporary Abstract Algebra", by Joseph Gallian is an algebra textbook that goes beyond just teaching material. It has quotations, biographies, puzzles and interesting applications of algebra.