Besides the books already mentioned, I would recommend looking into
some material on VB6, especially if you don't have much programming
experience. While much of the material will not be directly relevant
(and some out of date), a book specific to Visual Basic will go into
great detail on VB basics, classes, interfaces, events, ADO, COM, and
other items that you'd need if you are both serious and wish to be
efficient. Majority of VBA-specific material either skim these parts,
don't start at the beginning, or don't go far enough.
Coming from a curly-brackets programming background (C++ and Java), I
use Programming Microsoft Visual Basic 6.0 by Francesco Balena for
reference all the time, when developing Excel- and Access-based
solutions with VBA.