Application Security Guide For CISOs
The OWASP Application Security Guide For CISOs is free to use. It is licensed under the Creative Commons Attribution-ShareAlike 3.0 license, so you can copy, distribute and transmit the work, and you can adapt it, and use it commercially, but all provided that you attribute the work and if you alter, transform, or build upon this work, you may distribute the resulting work only under the same or similar license to this one.
The contributors to the OWASP CISO Survey also provided invaluable data for this guide.
For further information about the Application Security Guide For CISOs see the project page.