Best of Friends is designed to allow you to run Malefex scenarios without purchasing the main rulebook. All the scenarios contained in it are cut down versions of full games from other past or upcoming supplements:
The Hostage Situation - In Darkness, Dreaming A Friend in Need - Limbus Fatuorum (for re-release as "Fools Paradise") Ghost in the Machine - "Hollow Halloween"
The rules in this book do not cover the supernatural aspects of Malefex from the players' point of view, and offer no way for them to learn about them. No character creation or advancement is included. Other changes are the cut down combat system, a reduced range of skills for pre-generated characters, and no insanity/derangement rules.