I take it the idea is that we're to think of the authors by whom we've read the most titles. In my case, that might mean H. Rider Haggard; without checking, I'd estimate that comes to 25-30 different books.
But if "authors you've read the most" could mean authors whose books you've read and reread the most, my results would favor C. S. Lewis and J. R. R. Tolkien, since I've read (for example) Out of the Silent Planet about 16 times, Lord of the Rings about a dozen times, and so on. (Actually, I've read quite a few different Lewis -titles- too, since I've read all of his fiction, poetry, literary criticism and history, autobiography, theology, etc.)
Combining number of titles of books and also titles read multiple times, my major authors might include Lewis, Tolkien, Haggard, Dickens, Trollope, Shakespeare, Asimov, Dick, Machen, Hawthorne, Lovecraft, M. R. James, Lars Walker, V. S. Naipaul, Orwell, Waugh, Eric Newby, Chatwin, Jane Austen, et al.