Membership in Rotary is by invitation only. Paul Harris, the founder of Rotary, was the only Rotarian who was not invited to become a member by another Rotarian. At the first meeting in Chicago, Paul Harris invited a coal dealer, a tailor, and a mining engineer. These men of different vocation, trades, and professions formed the first Rotary Club. Paul Harris felt deeply a need to bridge the gulf between the learned professionals and those engaged in trade.

Above information taken from "How to Propose a New Member", Shirley Bonsell, August 1994