How to control table level access

Hi folks,

Is there a way to control table level access?  For example instead of allowing a power user to select from entire schema I want to only allow them to select from a few tables.  I thought I read about this somewhere but can't seem to find any information on this.  Essentially I have power users that are validating views that we modelers have developed and want to be able to run SQL against the source tables to understand the underlying data and test.  But we don't want to give them free reign to query every table in the default schema.

Thanks,

-Patrick