When Leonard Sheldrake, a lonely geologist, meets Freida at an exhibition of the works of Dutch artist Maurits Escher in Cambridge, Massachusetts, he's immediately smitten with love. But, when they part, he realizes he doesn't know Freida's last name or her address.

She hadn't signed the visitor's book and his only clue to her identity is the green coat she wore. He does know she's a widow and that there's a tragedy of some sort in her background.

Based on their limited conversation, Leonard also believes the attraction he felt for her was mutually shared. He's determined to find her. He meets and enlists fellow educators and occasional detectives Homer and Mary Kelly in his hunt for the elusive Freida.

Their quest proves as elliptical as some of Escher's works, confronting the seekers with more mysteries and several apparent murders as well as danger for both Leonard and Freida before the puzzles are finally solved and the couple reunited. Along the way the reader is treated to a tour of historic Cambridge.

No one writes such erudite, whimsical and entertaining mysteries as Jane Langton. I first encountered her "detective" Homer Kelly in the novel Dark Nantucket Noon, the second of the 18 books featuring the Kellys, and have been a fan of his and Mary's adventures ever since. Homer's puns may occasionally veer near silliness, but he is an academic and sometimes the world can use a bit of silliness.

If you're a fan of Maurits Escher, as I am, the illustrations and comments on his works are an extra attraction in this novel. Langton's books were normally illustrated by the writer.

We lost Jane Langton in 2018 at the age of 95. Fortunately, all of her books are still available to be enjoyed by readers of mysteries and fantasies. Most of the Kelly series is set in Massachusetts, the territory she knew best, though the detectives do venture abroad in a few.