We have not yet obtained a perfect theory of bubble formation. In this paper the perfect theory of the formation of bubbles in the case where the bubbles of vapor are nucleated spontaneously in pure liquid is presented. This is done by the systematization of the classical theory of M. Volmer (Kinetik der Phasenbildung, 1939) and the theory of D. Turnbull and J. C. Fisher [J. Chem. Phys.17, 71 (1949)] and it coincides satisfactorily with the experiment of K. L. Wismer [J. Phys. Chem.26, 301 (1922)].Theory must be advanced further so as to afford a perfect explanation of the processes of boiling, cavitation and the critical phenomena of the movement of soil moisture [S. Takagi,Monographs on Theoretical Soil Physics; Theoretical Considerations on the Thermodynamical and Kinematic Properties of Soil Moisture(not yet published)]. To effect this object, the author has calculated the rate of formation of bubbles at a surface. The theoretical value, however, of the negative pressure at which the liquid fractures does not coincide by any means with the atmospheric pressure in the process of boiling. This is true also in the process of cavitation and in the process of critical phenomena of the movement of soil moisture. Some other factors must be introduced in order to bring the theory to a state of practical value.