Breastfeeding has gone in and out of fashion over the past 25 years, but Harvard Common Press’ Nursing Mother’s Companion has not: the book is HCP’s bestselling title, having sold more than one million copies since it was first published in 1985, and the publisher just released a 25th anniversary edition that has been substantially revised.

HCP has published previous revisions of Companion over the years, but it estimates that at least half of this new edition—the sixth—has been revised and updated. Publisher Bruce Shaw said it is “the most radical revision we’ve done of the book,” and editor Linda Ziedrich said among the additions to this edition is new information on breast pumps, nursing after a cesarean, problems associated with epidurals, herbal remedies for low milk supply, and nursing after gastric bypass surgery. HCP’s first printing of the new edition is 25,000 copies.

Author Kathleen Huggins is well-known in the field and helped build interest in the book by talking about it to doctors and healthcare providers at conferences. “The book built itself through word-of-mouth marketing,” said Adam Salomone, director of digital initiatives. Companion is distributed by hospitals and insurance companies to their patients and clients; Shaw said hospitals buy it by the thousands, and “special sales have really been the driver for this book.”

This time around, HCP is parterning with Mead Johnson, which makes Enfamil formula. Although it would seem contradictory, the company is including excerpts on nursing from the book in pamphlets that it will give to three million new mothers, and is posting the excerpts on its Web site.

Along with the new edition of the book, which is a $14.95 paperback, HCP is publishing a Spanish-language edition and a spiral-bound Nursing Mother's Companion Breastfeeding Diary, priced at $12.95. HCP plans to bundle the book and diary but is not yet doing so. Other plans for the future include an iPhone app and an enhanced e-book with audio and video.