Article from 2008

Michel Siffre - scientist based in Paris, author of several books, including Beyond Time (McGraw-Hill, 1964) and Découvertes dans les grottes mayas (Arthaud, 1993).

Joshua Foer - freelance science writer.

In 1962, a French speleologist named Michel Siffre spent two months living in total isolation in a
subterranean cave, without access to clock, calendar, or sun. Sleeping and eating only when his body told
him to, his goal was to discover how the natural rhythms of human life would be affected by living
“beyond time.” Over the next decade, Siffre organized over a dozen other underground time isolation
experiments, before he himself returned to a cave in Texas in 1972 for a six-month spell. His work helped
found the field of human chronobiology. Joshua Foer interviewed Siffre by email.

Whole interview here.