Calling the book The Island of Dr. Moreau serves two purposes. The first is the same as every good title: it's there to draw you in, to entice you to read the story. Many horror stories do this by having the name of its horrific element right in the title. Sometimes it's the person, creature, or spook that haunts the tale, such as Stoker's Dracula, Poe's "The Raven," or Ridley Scott's Alien. Other times it's the location where the horror takes place like Poe's "The Fall of the House of Usher," Craven's A Nightmare on Elm Street, or—you guessed it—Wells's The Island of Dr. Moreau.
The title also serves a second, more devious purpose, and that's to get you to think about the importance Moreau's island serves in The Island of Dr. Moreau. But isn't that kind of, you know, obvious? Yes, it is obvious, but most people only consider it obvious regarding the first purpose mentioned above—Moreau's island is the place where things go bump and boo in the night.
But if you think beyond that initial answer, all sorts of questions open up. Why didn't he just call it the Beast Folk; they're a horrific part of the story too, right? Why is it Moreau's island in the title? Why not The Island of the Beast Folk? The book is written in the form of a kind-of-sort-of memoir, so why not title it My Time Amongst the Beast Folk, or something like that?
We have a few suggests as to why the island should serve as the focus of the title in our "Setting" and "Symbols, Imagery, Allegory" sections, but don't forget to give these questions a shot too. See what you can come up with.