[plt-scheme] EOPL pre-requisites?

Hi folks,

Over the past few months I've been reading books on Scheme and asking
questions on the group and solving problems and writings bits of code
here and there. Moving forward I was to focus on one thing (time
limited of course), and I think that the "one thing" may be learning
about writing interpreters.

It looks like *the* book out there is Essentials of Programming Languages.

Folks say that this is one tough book, though. They go on and on about
it about the fact that it is so so challenging (and in the same breath
also say that no other book does as well a job).

For folks that think it is so tough what is the best way to prepare
myself before getting started with this book?