Robert-Jacques de Joly ((1887-07-05)July 5, 1887, Paris – November 13, 1968(1968-11-13) (aged 81), Montpellier) was a famous French caver and speleologist.
He was known for his physical strength and strong personality, and was responsible for inspiring and training many successful and influential cavers.
De Joly is credited with the invention of the lightweight, portable steel-cable ('electron') ladder, a tool that expanded the possibilities of cave explorations and became standard caving equipment for the next fifty years.
De Joly traveled throughout Europe and North America representing France at speleological conferences.
De Joly authored numerous articles and three books, including Ma vie adventureuse d'explorateur d'abîmes which was later translated into English as Memoirs of a Speleologist and continues to inspire generations of cavers today.