This book explores chemical bonds, their intrinsic energies, and the corresponding dissociation energies which are relevant in reactivity problems. It offers the first book on conceptual quantum chemistry, a key area for understanding chemical principles and predicting chemical properties. It presents NBO mathematical algorithms embedded in a well-tested and widely used computer program (currently, NBO 5.9). While encouraging a "look under the hood" (Appendix A), this book mainly enables students to gain proficiency in using the NBO program to re-express complex wavefunctions in terms of intuitive chemical concepts and orbital imagery.

FRANK WEINHOLD, PhD, is Emeritus Professor of Physical and Theoretical Chemistry at the University of Wisconsin–Madison. Professor Weinhold has served on the editorial advisory boards of the International Journal of Quantum Chemistry and Russian Journal of Physical Chemistry. He is the author of more than 170 technical publications and software packages, including the natural bond orbital program.

CLARK R. LANDIS, PhD, is Professor of Inorganic Chemistry at the University of Wisconsin–Madison. He has received teaching and lectureship awards for his contributions to chemical education. Dr. Landis's research focuses on catalysis in transition metal complexes.