The paper discusses the research results of the mutual interaction of a liquid and the heating surface. The mechanism of the process has been analysed. The second critical radius of the vapour bubble has been introduced which depends on the supersaturation degree of the gaseous molecules in the liquid. Under certain circumstances the second critical radius is less than the thermal one, and the formation of the vapour bubble is ensured by the diffusion mechanism. It was found out that essential change in the intensity of the exoelectron emission (EEE) heating surface occurs as a result of prolonged boiling, and a hypothesis has been advanced of the electron-emitting nature of the boiling centres. The obtained results explain the variations of the heat transfer coefficient in time and hysteresis of the intensity characteristic of the boiling process.