A few important topics to get you started as a player:
Rules -- Important guidelines on what is or isn't permissible in the world of HellMOO
FAQ -- Frequently Asked Questions.
Corporations -- Information on corporations
Corporation List -- List of various past and present corporations. Not up to date, but historically interesting.
Player-written guides -- Read what the "experts" on playing have to say!
Mail Commands -- A list of mail-related commands and a brief description of each.
Parser -- How your commands are interpreted.
Commands -- A list of useful commands.
Emoting -- Helpfile on emoting and list of social commands.
Skills -- All documented skills.
Areas -- All documented areas.
Items -- All documented item types.
Weapon List -- All documented weapons and their stats.
Armor List -- All documented clothing/armor and its stats.
Scavenge Tables -- All documented scavenging tables.
Character Creation -- How to create your character.
Henchmen -- Hiring and working with henchmen.
Mutations -- The available mutations.
Admins -- The admins (should you dare to interact with them).
PlayerArt -- Player art submissions, including the slashfic contest winners!
Mobs -- A list of the various creatures or people you may encounter.
Maps -- Some maps describing various areas.
Buffs and Debuffs - For easier grinding.
Shopping -- Where to get stuff.
Jobs -- A list for easy reference on various documented jobs.
Boating -- A simple introduction to boats.
Pilot -- A simple introduction to planes.
Implants -- List of implants.
Disease -- Information on diseases.
Cyberspace -- This is where you learn about the internet.
Blue prints -- Custom HQs etc
Research Simulators -- For the science nerds in you
Pop culture references -- One of the many reasons why Hellmoo is funny as hell.
Halloween - If it's the month of October you can read this, if not - too bad.