  We review and elaborate on some aspects of Born-Infeld action and its
supersymmetric generalizations in connection with string theory. Contents: BI
action from string theory; some properties of bosonic D=4 BI action; N=1 and
N=2 supersymmetric BI actions with manifest linear D=4 supersymmetry;
four-derivative terms in N=4 supersymmetric BI action; BI actions with
`deformed' supersymmetry from D-brane actions; non-abelian generalization of BI
action; derivative corrections to BI action in open superstring theory.
