Ward, Milledge & West’s High Altitude Medicine and Physiology, sixth edition, is the latest edition of this venerable, but hardly stodgy, book. As with the second through the fifth editions, it continues to improve. The book has come of age with the addition to the title of Michael Ward, James Milledge, and John West, authors of the first 3 editions. Milledge and West continued to the fifth edition and have now passed the baton to new, younger authors. Andrew Luks, the lead author of the sixth edition, joined as an author in the fifth edition. The other authors are all new to the book. Like Dr Luks, all of them are well-respected experts in the subject. The style is less sparse than in previous editions, but still clear and consistent. The authors have rewritten most of the material, rather than just revising the chapters, and have added a wealth of new material. New material includes updates throughout the book, based on new studies published since the fifth edition in 2013, and expansion of many areas, such as genetics and geography. The number of pages and the type size are about the same as in the fifth edition. The format of the sixth edition is larger to accommodate the additional material. The book is now divided into 3 sections: The Environment and Its People, Physiologic Responses to Hypoxia, and Clinical High Altitude Medicine. The chapters have been reorganized and rearranged. The 27 chapters, decreased from 29 in the fifth edition, are divided into many more subsections, making it easier to find information on specific topics. Another welcome change is that the references are now at the end of each chapter rather than at the back of the book. Every chapter is thoroughly referenced. Although any new textbook is already out of date by the time it is printed, this edition is as up to date as possible, with references as recent as 2020. The authors have once again anticipated future trends, pointing the way forward to help readers remain current between editions. Examples include genomic studies of high altitude adaptation and susceptibility to altitude illness, which continue to proliferate, and altitude preacclimatization. New studies of preacclimatization are likely after recently reported ascents of Mount Everest with climbers flying directly to base camp after arriving in Nepal. The authors mention that future editions are likely to include significant new information in these areas as well as others. My worst, but still minor, disappointment is that the iconic frontispiece photo of the original authors on skis during the 1960 Silver Hut expedition that graced the first 3 editions is still missing from the sixth edition. Ward, Milledge & West’s High Altitude Medicine and Physiology continues to be the foremost reference work on its subjects. It was a great pleasure to review the latest edition. I congratulate the authors on freshening and expanding the text. I recommend it to both experts and neophytes with clinical or research interests in high altitude. Before you put it on your bookshelf, preferably in easy reach so that you can refer to it often, you will probably want to read some, or even all, of the chapters.