Shaykh Ahmad chose Yazd as his temporary residence and wrote most of his books and epistles

A 14th Century mosque in Yazd (National Geographic 1999)

Having sown the seeds of Divine knowledge in the hearts of those whom he found receptive to his call, [in Shiraz] Shaykh Ahmad set out for Yazd, [about 190 miles northeast of Shiraz] where he tarried awhile, [until about 1816] engaged continually in the dissemination of such truths as he felt urged to reveal. Most of his books and epistles were written in that city. 

(The Dawn-Breakers, chapter 1)

A. L. M. Nicolas, in Chapter 5 of his book, “Essai sur le Shaykhisme,” gives a list of no less than ninety-six volumes as representing the entire literary output of this prolific writer. Among them, the more important are the following:

1. Commentary on the Ziyaratu’l Jami’atu’l-Kabirih of Shaykh Hádí.

2. Commentary on the verse “Qu’l Huvalláh-u-Ahad.”

3. Risaly-i-Khaqaníyyih, in answer to Fatḥ-‘Alí Sháh’s question regarding the superiority of the Qá’im over His ancestors.

4. On dreams.

5. Answer to Shaykh Musay-i-Bahrayní regarding the position and claims of the Sáhibu’z-Zamán.

6. Answer to the Súfís.

7. Answer to Mullá Mihdiy-i-Astirábádí on the knowledge of the soul.

8. On the joys and pains of the future life.

9. Answer to Mullá ‘Alí-Akbar on the best road to the attainment of God.

10. On the Resurrection. 

(Footnotes included by Shoghi Effendi, Dawn-Breakers, Chapter 1 of the Dawn-Breakers)