The pages of this book are printed single sided with minimal texts that leave large blank areas. There is a theme to the book as exemplified by three recurrent, similar pages scattered throughout the book. One is entitled "el libra de la forma" which is printed at the top right side along with a small empty circle in the middle of the page. Another is entitled "musica mentale" with a small straight line placed in different positions on the page. The final title is "musica visible" which is printed with lines that connect in different directions. -- Source of annotation: Marvin or Ruth Sackner.

The Zaj group of artists consisted of Hidalgo, Marchetti, Castillejo, and Ferrer. This catalogue includes photographs of pianos modified by Zaj for Archivo Conz. Thirty-two large scale silkscreen prints on cloth published by Conz of Zaj images are depicted. The Sackner Archive holds several of the originals which are often postcard size. -- Source of annotation: Marvin or Ruth Sackner.

Stored with Zaj material. The card depicts a regular grid of periods on a deep blue colored background. -- Source of annotation: Marvin or Ruth Sackner.