Concrete Mathematics is a blending of CONtinuous and disCRETE mathematics. "More concretely," the authors explain, "it is the controlled manipulation of mathematical formulas, using a collection of techniques for solving problems."
Concrete Mathematics: A Foundation for Computer Science

ISBN: 0201558025
ISBN 13: 9780201558029
Publisher: Addison-Wesley Professional
Authors: Ronald Graham, Donald Knuth, Oren Patashnik