This page http://www.haskell.org/ghc/documentation.html has a link to the September 2001 (Draft for GHC 5.02) document describing GHC Core (in what is for me user-hostile .ps.gz format.) And this page http://www.haskell.org/ghc/docs/latest/html/users_guide/ext-core.html promises an easier format PDF document, but the link is broken. I did eventually find the 1st April 2009 GHC 6.10 document here http://www.haskell.org/ghc/docs/6.10.2/html/ext-core/core.pdf and a bit on this page http://www.haskell.org/ghc/docs/latest/html/users_guide/options-debugging.ht... about GHC core. I haven't read these yet, but could I ask whether they constitute the complete current documentation for GHC core? (I'm just curious to get a flavour of what core does.) Richard.