Darwin Holmstrom has written, co-written, or contributed to more than thirty books on subjects ranging from motorcycles and muscle cars to Gibson Les Paul guitars, including Indian Motorcycles, GTO: Fifty Years, Let's Ride: Sonny Barger's Guide to Motorcyclying, Top Muscle: The Rarest Cars from America's Fastest Decade, BMW Motorcycles, The Life Harley-Davidson, and The Complete Idiot's Guide to Motorcycles. Darwin is a former senior editor at Motorbooks and former Midwestern editor for Motorcyclist magazine.

Randy Leffingwell wrote his first book, American Muscle, while still on staff at the Los Angeles Times. The book examined Times’ publisher Otis Chandler’s growing collection of muscle cars. American Muscle published in September 1990, jump-started a love of book creation that ultimately led Leffingwell to leave the Times in 1995. By then, he and Motorbooks had published Porsche Legends, and six other books.
 
Since 1990, Leffingwell has authored more than 60 titles, most of them automotive-oriented. Over 30-plus years, these include a dozen Porsche titles ranging from general overviews—Porsche 75 Years: Expect the Unexpected, and The Complete Book of Porsche 911—to deeper explorations in Porsche Turbo and Porsche 911: 50 Years. During this time, he has regularly traveled to Germany to continue his research regarding Porsche’s history. To date, Leffingwell has interviewed more than 200 Porsche engineers, stylists, model makers, racers, and managers.
 
While he has tackled other subjects including John Deere tractors, Harley-Davidson motorcycles, and West Coast lighthouses, Leffingwell admits he is almost addicted to the Porsche story. In addition to his book work, he is historical editor for 000 magazine and PorschePanorama. And for the past decade he has been researching and writing an encyclopedic history of Porsche’s motorsports endeavors.
 
Leffingwell lives near Santa Barbara, California.