This is a collection of short stories about the adventures of Sherlock Holmes. In the American edition, you can find 11 stories, and in any other editions, this number will be 12 usually. The Memoirs of Sherlock Holmes by Arthur Conan Doyle includes such stories as Silver Blaze, The Final Problem.
Also, you can find under the cover of this book short stories about the adventures of the Cardboard Box, the Yellow Face, the Stockbroker's Clerk, the Gloria Scott, the Musgrave Ritual, the Reigate Squire, the Crooked Man, the Resident Patient, the Greek Interpreter, and the Naval Treaty.
The Memoirs of Sherlock Holmes were firstly published in 1894 without a short story about of the Cardboard Box. It is some kind of a mystery because that story is really good and was published before 1894 in the Strand Magazine. The first American edition of the book had The Adventure of the Cardboard Box but not the second one. You may do not know, that in British Empire this story was removed at authors' request. Doyle did that because of adultery scene. So he tries to care about young readers.
The Adventure of the Cardboard Box was republished in the United States of America only many years later. And this delaying took place not only because of Doyle's request, but for another reason too. Some publishers thought that this adventure of Sherlock Holmes is too scandalous and the American people cannot accept it.