Great tutorial, or greatest tutorial?

http://en.wikibooks.org/wiki/Write_Yourself_a_Scheme_in_48_Hours
This must be the greatest tutorial available to people keen to learn both HASKALL and SICP's protagonist SCHEME _!!!!^!!!

Scheme is a Lisp, Lisps are implemented in Lisp with only the most primitive functions being part of the compiler. Any Lisp not written is Lisp is like writing a C compiler in Smalltalk