I have every one of Agatha Christie's around 113 novels and play adaptions (paper editions), and have enjoyed reading most of them more than once. Her books are way better than watching a condensed film version, so even if you've seen some of the TV series or movies, it is well worth trying some of her books.
At least three are also in the public domain on Project Gutenberg now, so can be found for free - The Mysterious Affair at Styles, Murder on the Links, and The Secret Adversary.
The linked article gives a short list of some of the best to try first, but I don't think I've read a single one of her books that I've not thoroughly enjoyed reading.
See
Where to start with: Agatha Christie#
crime #
agathachristie #
reading #
books #
literature 
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