From the introduction:
Flex6 is a universal system for pen-and-paper roleplaying games, with emphasis in consistent, streamlined rules, quick action resolution and high character customisation. It was designed from the ground up with the intention of providing a roleplaying rules framework that would enable players to design truly individual characters and emphasise the meaningful differences making them unique. To this end, one of the key concepts of Flex6 is dynamic abilities that can interact with each other and allow the player the freedom to determine his character’s strong and weak points.
This core version contains all the basic concepts and mechanics of Flex6 as well as a small selection of generic character abilities. Although it is not detailed enough to be used straight out of the box for anything but the simplest games, the core version serves as a demonstration of what Flex6 is and what it can do. A very simple game setting called “Bloodhunt” is included towards the end of the book to show how the base system can be expanded to serve the needs of a particular game.