We investigate the effects of linear and optimal non-linear control in
the simple case of one-dimensional unimodal maps. We show that linear
feedback relates unimodal maps to invertible ''Henon-like'' maps. Thi
s observation should be useful in relating the considerable bodies of
knowledge which exist far the two types of systems. in the case of the
optimal non-linear feedback scheme of de Sousa Vieira and Lichtenberg
we investigate the relationship between controlled and uncontrolled m
aps, particularly the preservation of the period doubling route to cha
os. (C) 1997 Elsevier Science B.V.