Time capsules have been used for thousands of years to store for posterity a selection of objects thought to be representative of life at a particular time. Such vessels have the dual purpose of causing participants to ponder their own cultural era and think about those to come.
This work is a cultural history of five thousand years of time capsules and other related time-information transfer experiences. It examines both the formal and the popular culture aspects of the time capsule, from its roots in ancient Mesopotamian and Egyptian building foundation deposits to the present utilization of spacecraft probes and other extreme locations. The deposits of 3000 BCE deliberately had no definite date and time to be opened; in 1876 CE came the idea of target-dated deposits. Also discussed are how "real" time capsules work, notional and archaeological time capsules, the height of the time capsule's popularity from 1935 to 1982, the preservation of writings in time capsules, keeping time in a perpetual futurescape, and turn of the century hype surrounding millennium time capsules.