The Four Dimensional Helicity Scheme Beyond One Loop

I describe a procedure by which one can transform scattering amplitudes computed in the four-dimensional helicity scheme into properly renormalized amplitudes in the 't Hooft-Veltman scheme. I describe a new renormalization program, based upon that of the dimensional reduction scheme and explain how to remove both finite and infrared-singular contributions of the evanescent degrees of freedom to the scattering amplitude.