by Annie Barrows
By the author of the Ivy & Bean books, this is a great little time travel book for young readers, and actually, this old reader enjoyed it too!
When Miri moves into an old house and finds a broken bit of an eyeglass, she has no idea it will transport her back to...the exact same house, but in the 1930s.
Not only does she have to find her way back to her own time and family, but she also has to try to rescue Molly, her 1930s doppelganger, who lives like a prisoner, terrorized by relatives who don't want her.
Rated PG because the relatives are kinda scary, and the suspense might get to you, too ;)