Abstract: A system of apparatus for the controlled directional drilling of a deviated well bore into the earth has a fluid operated drilling motor and drill bit secured on the bottom end of a drill string. The drill bit is supported for angular drilling relative to a substantially vertical well bore by either using a bent sub for supporting the drilling motor or by using a drilling motor with a bent housing or a combination of the two. A bypass tool is connected to the bent sub or motor housing, an orienting sub and mule shoe keying sub are connected to the bypass tool, and a surveying tool is connected in the drill string above the orienting sub and mule shoe sub. The bypass tool is in fluid connection with the motor and has a telescopic housing and a valve for circulating fluid into the bore hole to flush cuttings and debris therefrom. The surveying tool determines and controls the direction of drilling.