Tunnel Through Time

Tunnel Through Time is a 1966 science fiction novel written by Paul W. Fairman under American science fiction and fantasy author Lester Del Rey's byline. It is a children's time travel adventure.
Plot summary.
The novel tells the story of a teen named Bob Miller whose scientist father, Sam Miller, has invented a "time ring," a circular device that allows time travel. Bob and his friend Pete travel through time in search of Pete's father ("Doc Tom," a paleontologist) who has disappeared while traveling alone. Beginning in the Mesozoic Era (Tom's planned destination), the story depicts various adventures while the travelers jump from point to point in Earth's prehistory in search of the missing scientist, and their attempt to get home again.
Literary significance and reception.
This book was used in many elementary and middle school classrooms for reading and literature classes, and gained a notable popularity with its straightforward but dramatic writing style.
Publishing history.
The book was originally published in hardcover by the Westminster Press in May 1966 and in paperback by Scholastic Inc. It was reprinted several times, most recently in 1974.