Magnetic reconnection is believed to be the dominant coupling process at the Earth's magnetopause. The main features which characterise this process are the conversion of magnetic field energy into plasma energy, an associated change in the magnetic field topology, and the emission of high-energy (suprathermal) charged particles. A review is presented of the development of theoretical concepts of reconnection, starting with steady-state Petschek model. The topics covered include extension of Petschek's model for the time-dependent case, the switch-on and switch-off phases of reconnection, models of flux transfer events (FTEs), steady-state and time-dependent reconnection in compressible plasma, acceleration of plasma through the system of large-amplitude MHD waves, acceleration of charged particles in the diffusion region, the role of the surface waves.