  We show how generalised unitarity can be used to determine the one-loop
dilatation operator in N=4 super Yang-Mills. Our analysis focuses on two
sectors, namely the bosonic SO(6) sector and the SU(2|3) sector. The
calculation is performed on shell, with no off-shell information introduced at
any stage. In this way, we establish a direct connection between scattering
amplitudes and the dilatation operator of the N=4 theory.
