Perfected by the likes of Curt Flood and Lou Brock. Those guys would steal you blind.
I don’t really remember Flood stealing much, (maybe a 100 or so lifetime?), but besides Brock and Wills, the 1960’s really big time stealers I remember are Aparicio and Bert Campaneris. Willie Davis for maybe a few years also. Probably a few others in there my old brain is forgetting.