The article is devoted to a fundamental theoretical problem, which is connected both with legal theory and constitutional law. The author explores content of terms «constitutionalism», «false constitutionalism», «constitutional state», «political constitution», «rule of law»and their understanding in different countries and in various time periods. The article analyses the role of Russian legal scholars in studying this issue. The author emphasizes the tendency developing in many countries to study the constitutional law in collaboration with such disciplines as administrative and financial law.