The article is the first publication of the correspondence between prominent Russian historians of science Dr. Sci. S. I. Romanovsky and Dr. Sci. V. A. Sokolov covering the period 1977–1983 and dealing mainly with the principles and challenges of writing scientific biographies through the example of geologists A. P. Karpinsky, A. A. Inostrantsev, V. M. Timofeev, P. A. Borisov, P. A. Puzyrevsky, F. Yu. Levinson-Lessing, G. P. Helmersen. Special attention is paid to the priority in the discovery of the facies law of Golovkinsky – Walter – Inostrantsev. The relationship between empirical and theoretical aspects in geological science is discussed. The article is addressed to historians of science, first of all to researchers of the geology of Karelia.