The John F. Kennedy Presidential Library has this neat page on Kennedy Family biographies. This includes biographies of many prominent Kennedy family members, a Kennedy family tree, and profiles of close associates of President Kennedy.
From the site:
This section contains biographical summaries of the early life and presidential career of John F. Kennedy. Biographical profiles of the President’s family members and close associates may also be listed. These biographies are written at an eighth grade level and are suitable for basic research purposes.