Two stories containing search for thumb on scales

A recent thread mentioned the "Foundation" character Arkady Darell.
That brought to mind Jean Morrel in A.C. Clarke's "Childhood's
End." Both women are instrumental in locating the home bases of
totalitarian powers that orchestrate events. (Their names even
have a similar ring: Darell/Morrel.) This raises the question:
Is there anyplace else in SF literature besides Asimov and
Clarke that feature remote, vaguely-defined powerful entities the
sussing out of which are a preoccupation of some of the characters?
I guess this could be considered a subset of stories that
feature any type of decoding of mysteries.