Site directed mutagenesis

[Dr. S. Bhattacharya]

Hi netfolks
Could someone recommend a good reference on the principles of site
directed mutagenesis for the investigation of enzyme function.
We have no problems with the technique, but I would like to know
more about the general strategy, i.e. which mutants are likely to
provide the most information, what amino acid changes to make, and
where to make them.
Shoumo