The main difference between the Choose Your Own Adventure series and the Time Machine series was that Time Machine books featured only one ending, forcing the reader to try many different choices until they discovered it.
Also, the series taught children basic history about many diverse subjects, from dinosaurs to World War II.
Only the sixth book in the series, The Rings of Saturn, departed from actual history; it is set in the future, and features educational content about the solar system.
Some books gave the reader their choice from a small list of equipment at the beginning, and this choice would affect events later in the book (e.g. "If you brought the pen knife, turn to page 52, if not turn to page 45.[1]").
The line spawned a brief spin-off series for younger readers, the Time Traveler novels.