Herman Melville, the author of Moby-Dick, is the subject of a new Google. Actually the book itself is really the subject, as a mouse-over indicates (not to mention the image itself), but if you click on the doodle, you're taken to Google's search results for the author.
The day marks the 161st anniversary of the book's publication. It was originally published on October 18, 1851 in Britain. The U.S. publication date for the book was November 14, 1851.
In some parts of the world, it is already October 18, and Google is showing the doodle. As of the time of this writing, you can see it on Google's Australia, New Zealand, and India sites, for example.
If you do click on the doodle and view the results for "herman melville," you'll be greeted with Google's Knowledge Graph entry for the author. It gives you the basic info (birthday, death date, spouse, education, etc.) with a link to Wikipedia, and below that, it points you to various books he has written and other authors that "people also search for," which include Mark Twain, Charles Dickens, Nathaniel Hawthorne, Arthur Conan Doyles, and H.G. Wells.
Clicking on any of the books will take you to their respective Knowledge Graph results, which point you to Google Books pages. If you search for Moby-Dick itself, it will also point you to Google Books, where you can purchase the ebook.