I have read Lao Tzu's TAO TE CHING several times during the past couple of decades, and I am still learning from it! I also enjoy reading books on this subject as well as Zen Buddhism.
Currently, I am reading THE TAO IS SILENT by Raymond Smullyan, originally published in the late 70s. He is a mathematical logician, and I like his perspective!
I also want to read more by DOGEN. What little I've read has enlightened me.