I recently received this question in an email and here is my answer.
When people ask this question, they usually want to know the specifics of a past life. Where? When? Were they famous? What year were they born? How much money did they have in the bank? These are not the best questions to ask. People usually ask this because they want to be more aware of their own potential; they feel restricted by the situations of their life. They want to know what they could achieve if someone placed them in a completely different situation. If you are asking this question, for these reasons, it is better not to know the situations of your past life. To compare two lives would give you a greater perspective of your own limitations. Not knowing would allow you to believe in greater possibilities. You would be more likely to move beyond the past life and go for greater objectives.
This isn't something I discussed in Death and Rebirth. In the book I focused on who we become in each life. How we love and the lessons we face, became more interesting to me than the specific situations of a life. The book includes the common aspects of the first four lives we experience.