From the introduction: The difference between what you will find in these pages and the solo system presented in Appendix O of the Dark Streets & Darker Secrets rules is the definition of ‘solo.’ The rules in Appendix O refer to solo as being one GM and one player. A group that doesn’t have the back up of an entire party of characters, with their range of skills and abilities. The solo that this book deals with is true solo or solitaire play. These rules dispense with the GM and replace that role with a few random tables and improvisational prompts.