"The Adventures of Sherlock Holmes" by Arthur Conan Doyle
"My dear fellow," said Sherlock Holmes, as we sat on either side of the fire in his lodgings on Baker Street, "Life is infinitely stranger than anything which the mind of man could invent. We would not dare to conceive the things which are really mere commonplaces of existence. If we could fly out of that window hand in hand, hover over this great city, gently remove the roofs, and peep in at the queer things which are going on, the strange coincidences, the plannings, the cross-purposes, the wonderful chains of events, working through generations, and leading to the most outre results, it would make all fiction with its conventionalities and foreseen conclusions most stale and unprofitable."
"The Adventures of Sherlock Holmes" is a collection of stories that first appeared in 1892. Doyle wrote many other Sherlock Holmes stories and novels, the most famous being "Hound of the Baskervilles." He wrote books centered on other characters as well, and his Professor Challenger stories were also quite popular during his lifetime.
I'm not a big fan of detective novels, but these stories are all good. Sherlock Holmes is an absorbing character, and it is easy to understand his enduring popularity. None of these stories are especially deep, but most of them are very, very clever.