about

private eye
... from the term private investigator,
the "i" of investigator being changed to "eye,"
which plays on the idea of a person looking into things.

The American Heritage Dictionary of the English Language, 4th Ed.

anon
Abbrev. of ANONYMOUS a. Hence as n. , a person (esp. a writer or composer) whose name is unknown or not given

anon , adv.
strictly , Straightway, at once, forthwith, instantly.

Oxford English Dictionary