Couple more Nethack links for the day. Beginners Guide for NetHack. Its an absolute must read if you want to survive more than a half dozen levels or so.
For a funny but entirely feasible journey into the NatHack universe check out planetfargo’s A guided Tour of NetHack. Its funny cause its true.
Finally, if you had a wand of polymorph what NetHack Monster would you be. Take the test and fine out. FYI I would be a cockatrice.