Schwarzenegger, 64, has given the book the working title of "Total Recall: My Unbelievably True Life Story," People reported Thursday.
"He has been keeping notes and working on the book for over a year," his spokesman Adam Mendelsohn said. "He didn't want to write his autobiography while he was governor."
A source added, "This book will not be a tell-all."
The former California governor will work on the tome between shooting scenes for his next film "The Expendables 2," with Sylvester Stallone.
Jonathan Karp, of publisher Simon & Schuster, said, "Nobody has a life story even close to his. Truly, Arnold is one of the most fascinating figures of our time."
Schwarzenegger and Shriver ended their 25-year marriage earlier this year after it was revealed he had fathered a love child with the family's housekeeper, Mildred "Patty" Baena.