Ellen Raskin won the Newbery medal for it in 1979, and we are still reading it today.
When eccentric millionaire Sam Westing dies, he calls together his 16 heirs, a strange assortment of people who seem to have nothing in common except, of course, for the fact that they've all recently purchased apartments in the Sunset Towers luxury complex.
They are all summoned by Westing's lawyer to the will reading where they learn that Westing was murdered! They are grouped into preassigned pairs, and each pair receives a set of clues and a check for $10,000. The first pair to solve the mystery will inherit Mr. Westing's 200 million dollar estate!
The race is on, but with a murderer on the loose, no one is safe, and everyone is a suspect!