I recently downloaded Lady Susan by Jane Austen and was astounded to see it is only 82 pages long. The next day I began The Jungle Book and was surprised at its modest length. Naturally, I felt compelled to make a list of works by classic authors that are about 100 pages or less. I linked to Kindle Free titles whenever possible, so without further ado, here is the list. . . .
A Child's Garden of Verses by Robert Louis Stevenson (77 pages)
Aesop's Fables (this version is 104 pages)
The Call of the Wild by Jack London (68 pages)
The Dead by James Joyce (80)
The Death of Ivan Ilych by Leo Tolstoy (54)
Dr. Jekyll and Mr. Hyde by Robert Louis Stevenson (61)
Elements of Style by E.B. White (the only non-fiction title here, 93 pages)
Heart of Darkness by Joseph Conrad (94)
The Hound of the Baskervilles by Arthur Conan Doyle (117)
Just So Stories by Rudyard Kipling (89)
The Legend of Sleepy Hollow by Washington Irving (74)
The Man Who Knew Too Much by G.K. Chesterton (87)
Metamorphosis by Kafka (50)
Of Mice and Men by Steinbeck (73)
O Pioneers (101 pages)
Rikki Tikki Tavi by Rudyard Kipling (73)
Rip Van Winkle by Washington Irving (25 pages)
The Time Machine by H.G. Wells (90)
The Turn of the Screw by Henry James (103)
Also, each Shakespeare play can be read in 2 to 3 hours.
Abe Books has a similar list here.
Did I miss any? Please feel free to make suggestions in the comments.