This short series of time travel stories is about children who reach out of their own time periods to touch others living in the past and in the future in order to change their world for the better. The series centers on themes of climate change and war and how we respond to changes in the world around us.

The series organization is somewhat unusual because the second and third books basically describe the same events but from different perspectives. Unfortunately, I don’t have the first book right now and haven’t read it, but according to reviews that I’ve read at Goodreads, it has different characters from the later two books but similar themes, especially the environmental ones. The action generally takes place in Scotland at various periods of time, past, present (from the perspective of when the books were written), and future (late 22^nd century, after climate change and war have significantly altered the geography and political systems of the world).

Books in the Series:

In the Keep of Time (1977)

Four children who are staying with their great aunt in Scotland explore the old keep of a nearby castle and are taken back in time to the reign of James II in 1460 through the use of a magical key. When the youngest girl in the family seems dramatically changed by their time travel experiences, they try the key once more, ending up in the future.

In the Circle of Time (1979)

In a mysterious circle of standing stones, Robert and Jennifer cross over into a distant future, where the world has been devastated and changed forever by pollution, climate change, and war.

The Mists of Time (1984)

In the future, the late 22^nd century, a girl named Lara learns that she has the ability to contact people from other time periods, crossing borders between times at certain special places. When her people are captured and enslaved by others, Lara attempts to use her gift to seek help from the past. (This is mostly a retelling of the events of the second book in the series from a different perspective.)