It started out as a live-action series broadcast on the San Francisco TV station KRON in 1951. In 1953 the series was aired on the Los Angeles TV station KTTV, again live action. All 51 live-action episodes were 15 minutes in length.
In 1954 the series was picked up for syndication. Episodes were shot on videotape and to fit in a 30-minute time slot. There were 26 half-hour episodes.
The opening credits were shown on the series finale of another time travel series, Quantum Leap (1989): Mirror Image - August 8, 1953 (1993).