A book in a dream often represents knowledge you're seeking or a story about yourself that's still being written. An unreadable or blank book can point to self-understanding that feels just out of reach, while finishing one may reflect a chapter of your life reaching genuine closure.
Consider what things the Planets perform not by their Aspects, and observe if they do them not by their Antisions, for the Antisions have power, and are not to be enumerated amongst Aspects. - William Lilly (1602.-1681.)