This paper summarizes research that has been done with systems as research object. It has been defined the concept of “system” and other fundamental concepts of system analysis. The relationships between these concepts has been formulated in the form of axioms, and based on these axioms, the general theory of systems was developed as a particular case of the L theory of calculus of statements. Finally, from the analysis of these studies, we can conclude that: it is possible to apply system analysis to any type of organisation, which is investigated by other branch of science, since system analysis is an independent branch of science.