This book focus on the theoretical and practical methods of designing An Exhaust Thermoelectric Generator (ETEG) to harvest as much exhaust wasted heat from class 8 hybrid truck muffler as possible and convert it to electric power. Seven chapters explain how this design formulated designed and worked to produce 1.2 kW of eclectic power. The rules of heat transfer have been applied in calculating, designing and choosing a 0.4 m outside diameter nonagon heat exchanger, a cold plate and an exhaust radiator. A prototype was also designed and tested in the thermal laboratory to simulate the electric power generated from the ETEG.