Let {ei,Ei} be a total
biorthogonal system in a linear topological space X. The multiplier algebra of X with
respect to {ei,Ei} written M(X) is the set of all scalar sequences (t(i)) such that for
each x ∈ X there is y ∈ X with
The form of M(X) is determined when {ei,Ei} is a norming complete biorthogonal
system in a Banach space or a basis in a complete barreled space. It is shown that a
sequence space is the multiplier algebra for a basis in a Banach space if and only if it
is a γ-perfect BK-algebra.