"A Journey Through Time" is a paperback book written by H.G. Tannhaus, Winden's clockmaker. The publishing house Minotaurus printed a 500-copy edition of the book in 1981.
The work contains the basic theoretical framework for time travel: Einstein-Rosen bridges, wormholes, the Bootstrap Paradox, the lunar-solar cycle, and much more. The author's fundamental hypothesis is: Time is not linear. Past, present, and future are intertwined and influence one another.
A Winden Bestseller
Helge Doppler gifts Claudia Tiedemann the book in 1986, upon her being named director of the nuclear power plant. He also has his own copy. In 2019, Ulrich Nielsen finds the book in the nursing home on Helge's nightstand and takes it with him.
In 1953, Ulrich shows the book to the clockmaker. It is the first time H.G. Tannhaus has ever seen it. The Stranger has also read the book and discusses its contents in depth with the clockmaker during his visit in 1986.