Henry Ernstthal’s research covered a broad range of questions. Ernstthal identified restaurants and other meeting places in addition to significant individuals referenced in the Diary. These assignments led him to delve into old business directories and back issues of the New York Times and other newspapers of the time.
Ernstthal was born and raised in New York. After graduating from Wesleyan University and Stanford Law School, he built a career working for associations as an executive director, as the director and fulltime faculty member of the Masters Degree Program in Association Management at The George Washington University, and as a consultant and trainer.