Stephen J. Hagen, in American Journal of Physics, Vol. 72, No. 10, pp. 1359-1360, October 2004. Philip Nelson has done an important service in writing "Biological Physics: Energy, Information, Life." This creative and insightful textbook brings definition to the field and establishes a set of central themes, based on principles of statistical physics. Starting with very simple and general discussions of energy and order, Nelson builds up a rigorous set of statistical and thermodynamic models for understanding the molecular machinery of life. Always maintaining a solid physics perspective, he explores biological macromolecules, their structures and self-assembly, biomotors and locomotion, neurons, and more. The book is... a fascinating tour that will bring the reader within reach of many current research topics... These days physical scientists need to understand more biology, just as biological scientists need to understand more physics. Nelson's engaging and satisfying book opens the doors in both directions. It will intrigue both the student and the professor.