This fully revised and expanded second edition of a highly popular book covers the physical chemistry of biological macromolecules and how to study it using up-to-date experimental techniques. The approach used in the book is experimental because this is the way science actually works, and in addition the subject does not yet have the rigorous theoretical understanding sometimes found in more mature areas of chemistry. As a result of this approach, the topic is generally regarded as fun and interesting which is why it poses fascinating challenges for both theoretical and experimental scientists. The updated edition includes a new chapter on imaging, which covers recent developments in a range of biomolecular imaging techniques. The chapter on circular dichroism has been fully revised to conform to more up-to-date convention and the section on multi-dimensional NMR has been improved. These revisions give the student an overview of the range of techniques available, together with the underlying physical basis, sufficient to act as a platform for more detailed treatment elsewhere. Other updates include recent developments arising from genome projects and a new additional section on foams and surfactants reflecting recent advances in biofoams, with topical marginal notes and brief explanation of surface tension. The note about units has been expanded to include other commonly used non-SI units (eg the calorie). The "References" and "Further Reading" sections have been updated for all chapters and the marginal notes revised and updated where required with new marginal notes added where appropriate. The level adopted in this tutorial text is suitable for early undergraduate years in chemical or physical sciences, however, since this interdisciplinary topic is often postponed to later years, the book can also act as a basis for more advanced study. Students in other areas of the biological sciences will also appreciate the less intimidating approach to physical chemistry in the book.