A logo is a symbol comprising of images and/or words that works as the visible face of the company.
Book logo designs therefore would have to associate with the book store or the publishing company as the case may be. Another unique aspect of book logo design is that they almost always carry the image of a book in some form or the other. However, the challenge for the designer will be to still have an element of uniqueness with the design while at the same time depicting the policies and ideas that the company stands for.
Even within the wider domain comprising of books in general, there are books on almost every conceivable topics. Be it books dedicated to kids to those dealing with higher philosophical thoughts, companies dealing with specific types need to be represented by suitable logos. The same applies to books dealing with academic topics as well.
Another unique segment of books that has emerged off late is the electronic books or ebooks that are meant to be read off a PC, tablet devices or dedicated ebook reading devices. Depicting such companies or bookstores dealing with ebook therefore poses a challenge of its own as the logo need to have the right balance of books in general as well as the electronic medium they are associated with.