In his forthcoming memoir, the late Sen. Ted Kennedy (D-Mass.) called his car accident at Chappaquiddick Island that killed Mary Joe Kopechne was "inexcusable" and that he has been haunted by the incident since for over forty years.

The book, entitled "True Compass" will be released on September 14, but it was obtained early by the New York Times and New York Daily News.

On July 18, 1969 Kennedy drove with Kopchne, who was a former campaign staffer for Sen. Robert Kennedy (D-N.Y.), off a bridge and into a pond. He was able to escape to safety, but left the young woman behind.

Hours later, Kopchne was discovered dead in the vehicle. Kennedy later pleaded guilty to leaving the scene of an accident and received a suspended sentence and probation.

Kennedy candidly discussed other tough times in his life, such as his brothers, President John F. Kennedy and Robert Kennedy's, assassinations.

The memoir was written with the help of a collaborator, Ron Powers, and was based on Kennedy's notes taken over the course of five decades and an oral history project commissioned by the University of Virginia.

Kennedy died last week from brain cancer at the age of 77.