Agatha Christie 
The Mysterious Affair at Styles [EPUB ebook] 

In her first published mystery, Agatha Christie introduces readers to the heroic detective, Hercule Poirot. This is a classic murder mystery set in the outskirts of Essex. The victim is the wealthy mistress of Styles Court. The list of suspects is long and includes her gold-digging new spouse and stepsons, her doctor, and her hired companion.