  We prove L^p estimates for the "biest", a trilinear multiplier with singular
symbol which arises naturally in the expansion of eigenfunctions of a
Schrodinger operator, and which is also related to the bilinear Hilbert
transform. In a previous paper these estimates were obtained for a simpler
Walsh model for this operator, but in the Fourier case additional complications
arise due to the inability to perfectly localize in both space and frequency.
