The Spectral Energy Distribution (SED) Machine is an Integral Field Unit (IFU) spectrograph designed from the bottom-up to classify transients. It is comprised of two subsystems. A lenselet based IFU, with a 26" × 26" Field of View (FoV) and ~0.75" spaxels feeds a constant resolution (R~100) triple-prism. The dispersed rays are than imaged onto an off-the-shelf CCD detector. The second subsystem, the Rainbow Camera (RC), is a 4-band seeing-limited imager with a 12.5' × 12.5' FoV around the IFU that allows real time spectrophotometric calibrations with a ~5% accuracy. Data from both subsystems will be processed in real time using a dedicated reduction pipeline. The SED Machine is mounted on the Palomar 60-inch robotic telescope (P60), covers a wavelength range of 370 - 920nm at high throughput, and classifies transients from on-going and future surveys at a high rate. This will provide good statistics for common types of transients, and a better ability to discover and study rare and exotic ones. We present the science cases, optical design, and data reduction strategy of the SED Machine, as well as some examples from our comissioning run.