Retired college professor and inventor Howard M. Berlin lives in Wilmington, Delaware. He holds three United States patents for his inventions and is the author of over 30 books on diverse subjects, including World Monetary Units (2005) and The Charlie Chan Film Encyclopedia (2000). He has been collecting coins and banknotes of the Palestine Mandate for over two decades, has exhibited his collection widely, winning numerous awards and is a member of the Numismatic Literary Guild.