  Cohen Macaulay property of fiber cones of ideals is characterized in terms of
its Hilbert series. Hilbert series of fiber cones of ideals with minimal mixed
multiplicity is calculated. It is proved that the fiber cone of an m-primary
ideal I with minimal mixed multiplicity is Cohen-Macaulay if and only if its
reduction number is atmost one. Hilbert series of fiber cones of ideals
generated by quadratic sequences in standard graded rings is computed by
deforming it to a face ring of a simplicial complex. Applications are given to
defining ideals of monomial projective space curves lying on the quadric
xw-yz=0, straightening-closed ideals in graded algebras with straightening law
and Huckaba-Huneke ideals of analytic spread 1 and 2.
