A supercontinent with a keel down to the mantle transition zone (~400 km) is assumed to have existed during the early Archean (~4.0 Ga). The supercontinent (Rodinia?) was thinned and finally split into fragments with highly variable thicknesses (150~350 km) and sizes (1×106~17 ×106 km2) during the early and middle Proterozoic. Each fragment or craton is characterized by a thick Archean lithosphere surrounded by thin Proterozoic mobile belts. Since the late Proterozoic, these cratons have been stable without notable deformation and moved around Earth's surface. Unlike most of the cratons such as the Canadian and African ones, the North China craton (NCC) was reactivated during the Mesozoic and reduced its lithospheric thickness from 180~200 km in the Paleozoic to 80~100 km in the Cenozoic. The critical problems associated with the breakup and lithospheric thinning of the NCC are discussed in terms of rheology, with special focuses on the effects of various strain softening mechanisms (e.g., water weakening, reaction weakening, meltinduced weakening, structural layering weakening, recrystallization weakening, geometrical weakening, and superplasticity), heat deflection, and translithospheric shear zones (e.g., TanLu fault zone). The lithosphere beneath the QinlingDabieSulu orogenic belt, thickened by the Triassic collision between the NCC and Yangtze block, diverted heat coming vertically from the deep mantle away from the thickened southern margin of the NCC into the lithosphere beneath the Bohai Gulf and the SongLiao basins. It is emphasized that the lithospheric thickness is a more complicated concept than has been generally considered. The lithospheric thicknesses determined using different techniques (e.g., petrology, geochemistry, Swave tomography, wave receiver functions, low velocity zone, geothermal data, rheology, electrical conductivity, and water content) can contradict each other. Any conclusion about the lithospheric thinning obtained from a single technique should be crosschecked by other methods.