All the rulebooks in PDF format.
Note: The FAQ should be reviewed as it clarifies many things not clear in the rulebooks as well as containing errata for cards
Advanced FAQs 13.4 UPDATED 10/6 - Hosted on Heroscapers - 791.8 KB
Dungeons and Dragons Heroscape: Battle for the Underdark - 21.69MB
Swarm of the Marro Rulebook - Master Game & Scenarios - 27.5 MB (Hosted on rapidshare, better scanns by masterquetzal)
Swarm of the Marro Rulebook - Master Game & Scenarios - 5.81 MB (Hosted on Herocapers, Reduced filesize & uploaded by LeftOn4ya)
Road to the Forgotten Forest Instruction Book - 1.37MB
Volcarren Wasteland rules/scenario book - 885.89KB
Thaelenk Tundra Rule Book - 1MB
Fortress of the Archkyrie Rule Book
Ticalla Jungle Rule Book
Marvel: The Conflict Begins Rule Book (included here to have them all together)
Note: Below are the 1st and 2nd edition rules, these are outdated by the Swarm of the Marro Rules.
2nd Edition Rule Book - All 28 Pages (Includes: Basic Game/Master Game/Battlefields & Scenarios) - offline temporarily
2nd Edition Rule Book - Basic Game - offline temporarily
2nd Edition Rule Book - All 28 Pages - 23.67 MB (Hosted on Hasbro's site)
2nd Edition Rule Book - All 28 Pages - 4.44 MB (Hosted on Herocapers, Reduced filesize & uploaded by LeftOn4ya)
2nd Edition Rule Book - Battlefields and Scenarios - offline temporarily
1st Edition Rule Book - Basic Game - 30.1 MB (Hosted on Hasbro's site)
1st Edition Rule Book - Master Game Guide - 80.3 MB (Hosted on Hasbro's site)
1st Edition Rule Book - Battlefields and Scenarios - 11 MB (Hosted on Hasbro's site