|HSH The Prince of Lippe (who died earlier this year) and Arthur Addington.|
Arthur was one of the foremost royal genealogists. He spent many years researching the descendants of King James VI & I, which lead to the publication of his seminal work, Royal House of Stuart: The Descendants of King James VI of Scotland, King James I of England, published in 1969.
The book was published in three volumes, and is considered one of the masterful works of royal genealogy.
Arthur Addington was 76 years old. [Thanks to Ted Rosvall for allowing me to use this photo.]