Some of the earliest ones — like “Two Hundred Hidden Books ... puzzle craze has been threatened with extinction for so long that it will probably live forever.” Strands, our word search ...

This new puzzle is a word search with a unique twist ... word searches started to appear more in newspapers and activity books. Juliette Seive, a research director on the New York Times Games ...

or books that are themselves puzzles. But then there's Codex Silenda---a gorgeous, wooden book of brainteasers that is itself a multi-part mystery. As page-turners go, Codex Silenda is a special case.