It purports to be a collection of "forty-one actual case histories" of reincarnation and past-life experiences, gleaned from auditing with an e-meter at the Church of Scientology's "Fifth London Advanced Clinical Course" held in 1958.
Scientology's official website says of the book: "The major portion of the book is devoted to the auditing case histories of individuals, detailing their memories of past lives. These case histories graphically show how a person’s attitudes and actions in present time can be affected by incidents in his or her past lifetimes. They also document the improvements that occurred when such incidents were addressed and run out in auditing." Their promotional text for the book also goes on to note that the book answers important questions such as:
The book has been consistently in print until 1989. There are still copies for sale but it is not currently offered for sale today by Scientology's Bridge Publications and New Era Publications websites. There was no new edition in 2007 although 18 new editions of earlier Scientology books came out.
Journalist Paulette Cooper, a critic of Scientology and the target of harassment and a failed frameup for writing her book, The Scandal of Scientology, stated in her review of Have You Lived Before This Life:
"Most of the Scientologists who relived their past lives believed that they had once been plain people, or very often space people, and for plots, their histories read like a type of science-fiction sadomasochism. Many of the preclears believed that they had lived on other planets ... One preclear remembered that when he was in another life and was five years old he was "already on the lookout for brothels," by fourteen or fifteen had learned all about "sex and homosexuals," and by sixteen had killed his father, baby, and captain, breaking up the body of the last, before finally being taken away to the "Zap machine" where he was decapitated and his arms and body placed in a space coffin." 
Hubbard, who was extremely enthusiastic about the project, announced a sequel called Where Were You Buried? was in the works. He instructed his auditors to check all preclears for recent deaths, and then to physically locate their place of burial. The book was never released. (Ability, Number 114)
Some editions of the book have a question mark in the title, but most, including the first printing, do not. Later editions added the proper question mark missing from its title in the original printings. Adding to the confusion, some editions use the question mark on the dust jacket but not on the book itself.
The 1968 edition has 42 cases, some with names. The 1977 version has 41 cases, none with names. Those names (and time of incidents) was:
- Jesse Gray, Time: 651 years ago
- C. Sweetland, Time: 1874 A.D.
- Peter A. Davies, Time: 56 B.C.
- Ray Kemp, Time: Nine Galaxy Periods ago
- Anonymous, Time:  trillion years ago
- A.J. Cromie, Time: 1,600 years ago
- Don Hardy and Eileen Hibberson, Time: 3,225 years ago
- Cornelia Alford
- Anonymous, Time: 55,000,000,000,000,000,000 years ago
- Eve Harrison, Time: 6,254 years ago
- James Momsen, Time: 1804 A.D.
- Anonymous, Time: 469,476,600 years ago.
- Leon Bosworth
- Jenny Parkhouse, Time: 1,015,550 years ago
- Pamela Kemp, Time: 500 B.C.
- Anonymous, Time: 17th or 18th century A.D.
- Anonymous, Time: 1672 A.D.
- Adrian Potts, Time: 1500 A.D.
- Madge Stevens, Time: 1603 A.D.
- George Edwards, Time: 750 B.C.
- Edward Fuller, Time: 1666 A.D.
- Anonymous, Time: 1746 A.D.
- James Dimmock, Time: 54 A.D.
- Nadine Moeran, Time: 1903 A.D.
- Chris Mostart, Time: 11th Century A.D.
- Lance Harrison, Time: 5,100 years ago
- Clarence Killip, Time: 856 A.D.
- Jessie Gray, Time: 3 A.D.
- Herbert Parkhouse, Time: 1800 A.D.
- Mike Furse, Time: 1703 A.D.
- William Dicks, Time: 1824
- Marianne Christie, Time: 23,064,000,000 years ago
- Jack Campbell, Time: Seventy-six trillion years ago
- John Fudge, Time: 2,000,000,000 years ago
- Ann Fox, Time: 3,750 years ago
- Anonymous, Time: 17,543 years ago
- Jean Gill, Time: 25,016 years ago
- Alix Stansfield
- Carl Jensen, Time: 549 B.C.
- Ability (Scientology newsletter) number 114.
- Russell Miller. "Bare-faced Messiah, The True Story of L. Ron Hubbard" // Henry Holt & Co, New York, First American Edition, 1987, ISBN 0-8050-0654-0, chapter 14: Lord Of The Manor, p.238
- New Era Publications: Have You Lived Before This Life? Template:Waybackdate
- Scientology Library: Have You Lived Before This Life? Template:Waybackdate