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.
He that has too great a conceit of himself will be apt to fall into many errors in his judgement; yet on the other side, he that is too diffident, is not fit for this Science. - Cardan Girolamo (1501-1576)