John Jefferys was a board game designer from Westminster, England, who sold the first original board game in England on September 14, 1759.
He may have been the same John Jefferys (died in 1754?) who was an inventor and freemason brass artisan from Midgham, a village in Berkshire, England. This man was probably most famous for helping John Harrison, the English clockmaker who won the prize for inventing the marine chronometer, a long-sought device needed to determine longitude measurements for ships at sea. In 1735, he became the mentor to apprentice Larcum Kendall, a British watchmaker who was asked by the Board of Longitude to copy and develop John Harrison's inventions. One of Jefferys' clock maker apprentices was Jethro Tull (1725-1774), presumably a relative of the famous agriculturist and inventor also named Jethro Tull (1674-1741).
Note: The above information assumes that the clockmaker named John Jefferys is the same person who invented the game A Journey Through Europe.
He is believed by some to be the first game designer. However, the rules to "A Journey Through Europe" refer to "the rules of Goose", thus Goose should be an earlier board game. Furthermore, Sir John Suckling (1609-1642), the English Cavalier poet who supposedly invented the card game Cribbage, died over 100 earlier.