Although The Hollow (also occasionally published under the title "After Hours") does not have one of Christie's clever openings, there's a depth to The Hollow that one doesn't find in many of Christie's other books (or in many other books). The characters - somehow they're truer, more real, than others - especially John Christow, whom we meet at length during the first few chapters. Gerda Christow and Henrietta Savernake are also complex and genuine.
Other characters, even bit ones, are wonderfully and perfectly drawn. I know people like Lucy Angkatell. I know boys like Terence Christow, disappointed that his mother doesn't try to stop him from making nitroglycerin. I know children like Zena Christow, and her sticky-card fortune telling. And I especially appreciated this gem of a passage:
"Do you like telephones, David?"
It was the sort of question, David reflected irritably, that she would ask: one to which there could be no intelligent answer. He replied coldly that he supposed they were useful.