I have been looking through Ancestry's copious record collection for Sidney Kessler, primarily his travel records to and from San Juan and St. Thomas. There are also good census records of not only his married family but also his birth family, including this 1900 U.S. census that shows his family residence when he was three years of age. 

When born in Berlin in 1936, author Sue Key was already classified as “Mischling in the first degree.”