How do I really do this?

[Bruce Korb]

I would like to be able to associate a value with a string.
hash functions look perfect, except I can't use them unless
I have a hash table and there isn't any clear way I've found
to create hash table entries without having a hash table.
I've tried:

  (define (string->symbol (function-returning-string))
          (value-function))

I thought that to be really obvious, but I was wrong.
If either of these mecanisms are documented somewhere,
I'd gladly read it.  Meanwhile, can someone send me a hint?
Thank you. - Bruce