Academician Milko Borisov (1921–1998) was a prominent Bulgarian physicist, professor of solid-state physics, influential member of the Bulgarian Academy of Sciences, who laid the foundations of acoustoelectronics in Bulgaria and trained several generations of researchers. His systematic scientific results and memories of the development of physical sciences in Bulgaria are supported by sources containing the assessments of Acad. Georgi Nadjakov, Acad. Hristo Yankov Hristov, Corresponding Member Yordan Kasabov, and Prof. Paraskeva Simova on his half-century of scientific activity. The index of personal names mentioned in the book supplements the biographical data on the physicists who worked with Acad. Milko Borisov in the second half of the 20th century.