In the novel "Moby Dick" what type of creature is Captain Ahab looking for?

"Moby-Dick"; or, "The Whale" is an 1851 novel by American writer Herman Melville. The book is the sailor Ishmael's narrative of the obsessive quest of Ahab, captain of the whaling ship Pequod, for revenge on Moby Dick, the giant white sperm whale that on the ship's previous voyage bit off Ahab's leg at the knee. "Moby Dick" was a commercial failure, and was out of print at the time of the author's death in 1891.

William Faulkner said he wished he had written the book himself, and D. H. Lawrence called it "one of the strangest and most wonderful books in the world" and "the greatest book of the sea ever written". Its opening sentence, "Call me Ishmael", is among world literature's most famous.

He began writing "Moby Dick" in February 1850, and finished 18 months later. He drew on his experience as a common sailor from 1841 to 1844, including several years on whalers.

The book's ending is based on the sinking of the whaleship Essex in 1820.

Herman Melville (August 1, 1819 – September 28, 1891) was an American novelist, short story writer, and poet. Among his best-known works are "Moby Dick" (1851); Typee (1846), and "Billy Budd, Sailor", a posthumously published novella. Although his reputation was not high at the time of his death, the 1919 centennial of his birth was the starting point of a Melville revival, and "Moby Dick" grew to be considered one of the great American novels.