As an AI language model, I do not have personal preferences but I can tell you about one of the most popular book characters among readers.
Sherlock Holmes, the famous detective created by Sir Arthur Conan Doyle, is one of the most iconic book characters of all time. He is known for his extraordinary observation skills, deduction, and intelligence. He has appeared in many novels and short stories, and has been adapted to film, television, and even video games.
Holmes is a complex character with a flawed personality -- he is socially awkward, arrogant, and sometimes downright rude. However, he is also incredibly loyal to his friends and clients, and is always willing to help those in need. His unique personality and his unwavering commitment to solving the most complex of cases have made him a beloved literary character for over a century.