The authors and publisher are pleased to present the twenty-seventh edition of Harper’s Illustrated Biochemistry. First published as Review of Physiological Chemistry in 1939 and revised in 1944, it quickly gained a wide readership. In 1951, the third edition appeared with Harold A. Harper, University of California at San Francisco, as author. Dr. Harper remained the sole author until the ninth edition and co-authored eight subsequent editions. Peter Mayes and Victor Rodwell joined as authors in the tenth edition, Daryl Granner in the twentieth, and Rob Murray in the twenty-first edition. We now bid a fond and grateful farewell to our long-time colleague ....