This book provides an overview of select army research laboratory studies on carbon nanotubes. Topics include increasing the capacitance of carbon nanotube (CNT)-or graphene-based supercapacitors by adding pseudocapacitive manganese oxide nanoparticles; electrochemical double layer capacitors fabricated using carbon nanotube (CNT)/paper flexible electrodes; improving microbolometric response using carbon nanotubes; nanomagnetics-magnetic nanoparticles filled carbon nanotubes; and the performance of carbon nanotubes in extreme conditions and in the presence of microwaves.