Join Date: Jun 2008
Location: The United Kingdom
The current rules manual is the most up-to-date version of the rules and it includes 'all the Errata for the Original Rulebook and Rising Powers Book as well as including extra Diagrams, Quick Reference and a comprehensive Index.'
There is a downloadable version of this available on the Malifaux website that is a cut down version. It has all of the rules you need to play the game but some extras have been cut out to keep it simple.
Then there is the Twisting Fates expansion book that gives you some additional rules for Avatars along with stats for all the Avatars of Masters released up to that point. It also includes the next chapter in the engaging Malifaux storyline. However this expansion is not needed to play the game, only an additional extra like Apocalypse.
Hope that helps?