So what is the book that I should read? What is the Taoist bible?
It’s great that you want further your study of Taoism and explore the Tao. There is no Taoist Bible. Westerners typically expect the response to be the Tao Te Ching, or the Tao of Pooh.
The text that is the most important to Taoism is the I Ching. It is likely the oldest, and most foundational, spiritual text. However, the I Ching is difficult to understand and is really an “insider’s text,” meaning you already need to have knowledge of Taoism to use it effectively.
Taoism is an oral tradition, with nearly all the teaching done orally. It is not a text tradition.
Western religions are text traditions with the text believed to contain actual divine truth. In Taoism, texts are intended to be instructional manuals for specific schools or practices, or they function as inspirational literature to fuel one’s desire to pursue Taoist practice.