Dear Shabnam Nadjafi,
It is free to use Chimera in publications.  However, we request citing the program as described here:

<http://www.rbvi.ucsf.edu/chimera/docs/credits.html>

Thanks for your interest, and best wishes in publishing your book!
Elaine
-----
Elaine C. Meng, Ph.D.
UCSF Chimera(X) team
Department of Pharmaceutical Chemistry
University of California, San Francisco

> From: Shabnam Nadjafi <shabnam.nadjafi@gmail.com>
> Date: Monday, September 17, 2018 at 12:29 AM
> To: "chimera@cgl.ucsf.edu" <chimera@cgl.ucsf.edu>
> Subject: Question for using Chimera 1.8
> 
> Dear Manager
>
> I am a pharmacologist and I decide to publish a book about drugs and some biochemicals by in silico evaluation of the chemical structures with biologic targets. I have to use the impressive software "Chimera 1.8". Would you please give me some information about this?
> Is it enough to cite "Chimera 1.8" in "Foreword" or "Preface" sections of the book?
> Is it free to use "Chimera 1.8" for publishing a book?
>
> Sincerely Yours
> 
> Shabnam Nadjafi
> M.D.
> PhD of Pharmacology
> Neuroscience Research Center, Iran University of Medical Sciences, Tehran, Iran