Possible Clues:

• Like what a tortoise has in volume
• Book robust defender
• But is such a book easy-going?
• Volume is difficult to support
• A book that's difficult to support
• Not easy to get sponsor for book
• It offers binding promise, but may be too much for one's pocket
• Book giving description of tortoise
• Book that's right bad, awful, covered by journalist
• Style of book binding