There are hundreds of books on the Dzogchen available to an avid practitioner.

Having received empowerment into the Dzogchen or Ati Yoga practice and oral transmission and pointing out instructions, certain texts can contribute:

Yeshe Lama

Supreme Wisdom: A Commentary on Yeshe Lama

The Yeshe Lama: Jigme Lingpa’s Dzogchen Atiyoga Manual

Considering that I received empowerment into the Dzogchen practice from Namkhai Norbu, I am partial to His teachings, of course.
Here are books available to the general public:

And restricted material for those that have been initiated by Namkhai Norbu: