  In this paper we calculate the tree level three-point functions of Vasiliev's
higher spin gauge theory in AdS4 and find agreement with the correlators of the
free field theory of N massless scalars in three dimensions in the O(N) singlet
sector. This provides substantial evidence that Vasiliev theory is dual to the
free field theory, thus verifying a conjecture of Klebanov and Polyakov. We
also find agreement with the critical O(N) vector model, when the bulk scalar
field is subject to the alternative boundary condition such that its dual
operator has classical dimension 2.
