Where can I buy the Book of Changes?

I ching or classical Chinese is very interesting to read.

Traditional Chinese medicine is related to the Book of Changes, but there are two books. The Book of Changes itself is a book. It's sold online, so you can find it yourself.

Traditional Chinese medicine is Huangdi Neijing and Treatise on Febrile Diseases.

It's all online.

In order to suit the public, I believe there are quite a few simplified versions, usually a classical Chinese text followed by a translation.