What music theory books should I read to learn electronic piano?

If you study electronic organ, I suggest you don't study music theory systematically first.

You can buy some books about electronic organ. The first few chapters of this book should talk about the basis of music theory. You should have a general understanding of music theory first. If you study systematically from the beginning, the effect will not be very good.

When your electronic piano course reaches level 7, the concept of chord should be clearer. Then you can learn some chord knowledge about music theory.

After learning the electronic piano, come back and study music theory systematically. You can choose Li Zhongguang or Tong Zhongliang's books.

The correct method of learning music should follow the process of practice-theory-practice.

I wish you success ~ ~ ~