Sometimes in the ED you just need to saddle up and face adversity... John Wayne said something once to the effect of “Saddling up requires one to always think of PE”. We cannot find the reference but read it on Buzzfeed so it must be true. PE always seems to be on the differential. Its ever-elusive, dropping people dead at will, and we’re left rolling the dice with D-dimer. Let's review PE, its classic presentations, how to diagnose, treat, and disposition.