How many volumes were there for Sherlock Holmes?

There are four volumes of Sherlock Holmes stories written by Sir Arthur Conan Doyle.

* A Study in Scarlet (1887)

* The Sign of Four (1890)

* The Adventures of Sherlock Holmes (1892)

* The Memoirs of Sherlock Holmes (1893)

It's important to note that these four volumes contain a total of 56 short stories and two novellas. There are also several other collections of Sherlock Holmes stories published later, often featuring stories written by other authors or adapted from Doyle's original works.