Similar is the case with the ocean. It keeps accepting any number of rivers that merge in it, and yet remains the same. Ocean and fire have no trace of satisfaction. Therefore limitless desires are compared to these two. The whole world is like a book, read it well.
Nature is the best teacher.
There are lots of things in this world to be known. You cannot find God by going through a book or by undertaking spiritual Sadhana. Reading books will only increase your doubts. The more intelligent you are, the more you get doubts. Developing compassion is the real Sadhana.