  Category theory provides a compact method of encoding mathematical structures
in a uniform way, thereby enabling the use of general theorems on, for example,
equivalence and universal constructions. In this article we develop the method
of additional structures on the objects of a monoidal Kleisli category. It is
proposed to consider any uniform class of information transformers (ITs) as a
family of morphisms of a category that satisfy certain set of axioms. This
makes it possible to study in a uniform way different types of ITs, e.g.,
statistical, multivalued, and fuzzy ITs. Proposed axioms define a category of
ITs as a monoidal category that contains a subcategory (of deterministic ITs)
with finite products. Besides, it is shown that many categories of ITs can be
constructed as Kleisli categories with additional structures.
