In our article we could only speculate as to how and when Klein's mineral collection was transported to Germany and on the origins of the type-written catalog (in German) that accompanies the Klein collection at Harvard University. From various items in the Klein family archives, and with the assistance of Lange and Kloos, we have been able to piece together a probable sequence of events as follows. Further to the publication of our article titled "Tsumeb: The Legacy of Wilhelm Klein (1889-1939)" in the November/December 2018 issue ( I Rocks & Minerals i 93 (6): 528-553), we have been contacted by two of Klein's grandchildren, Mr. Michael Lange and Ms. Barbara Kloos, who have generously shared with us further details about their grandfather and his mineral collection. [Extracted from the article]