May Pang was the other woman to John Lennon's other woman, Yoko Ono.
The two years she spent with Lennon were his most productive as a solo artist, and his most famously debauched.
An older Lennon referred to those years as his "Lost Weekend" and may have regretted some of the public reporting of his lifestyle; but, there are no stories I've heard that differ terribly form the stories we all can tell about the years between 1973 and 1975.
This book follows Pang's earlier book about her time with Lennon, "Loving John."
Allan Kozinn writes a nice review of her new book at the New York Time site: A Fond Look at Lennon’s 'Lost Weekend'