He has co-authored many books with American chefs, such as Thomas Keller, Eric Ripert, Michael Symon and Jean-Georges Vongerichten.

While working at the magazine, Ruhlman wrote an article about his old high school and its new headmaster, which he expanded into his first book, Boys Themselves: A Return to Single-Sex Education (1996).

Ruhlman has also collaborated with chef Thomas Keller to produce the cookbooks The French Laundry Cookbook (1999), Bouchon (2004), Under Pressure (2008), and Ad Hoc At Home (2009), Bouchon Bakery (2012); with French chef Eric Ripert and Colombian artist Valentino Cortazar to produce the lavish coffee-table book A Return to Cooking (2002); and with Michigan chef Brian Polcyn to produce Charcuterie: The Craft of Salting, Smoking and Curing (2005) and Salumi: The Craft of Italian Dry Curing (2012).

Much of the insight in the book is based on his previous food-related experiences at the Culinary Institute of America and from working with celebrity chefs.

[citation needed] 2009, he published Ratio: The Simple Codes Behind the Craft of Everyday Cooking, a book that explores basic preparations—bread, pie dough, custards—and explains that knowing the proportions of the ingredients by weight can free users from strict adherence to recipes.

Ruhlman also released his first Kindle single book called "The Main Dish" which is about his long journey to become a food writer and then "The Book of Schmaltz: A Love Song to a Forgotten Fat" a single-subject cookbook devoted to the ingredient called schmaltz; rendered chicken fat flavored with onion which is popular in Jewish cuisine.

In the fall of 2015, he published his first fiction, In Short Measures: Three Novellas, stories about love in middle age and his first non-food-related work since his 2005 memoir.