  All most all the function spaces over real or complex domains and spaces of
sequences, that arise in practice as examples of normed complete linear spaces
(Banach spaces), are reflexive. These Banach spaces are dual to their
respective spaces of continuous linear functionals over the corresponding
Banach spaces. For each of these Banach spaces, a countable vector space basis
exists, which is responsible for their reflexivity. In this paper, a specific
criterion for reflexivity of a Banach space with a countable vector space basis
is presented.
