  In these lectures we present our minimality theorem by which in cohomology of
a topological space appear multioperations which turn it ot Stasheff
$A(\infty)$ algebra. This rich structure carries more information than just the
structure of cohomology algebra, particularly it allows to define cohomologies
of the loop space. We present also the notion of $C(\infty)$ algebra and the
commutatitive version of the minimality theorem by which in rational cohomology
algebra appear multioperations which form a $C(\infty)$ algebra structure which
completely determines the rational homotopy type.
