Abstract: The object of this research is the work of the prominent figure of the Bourgeois Revolution in France, one of the most remarkable French philosophers and public character of the Age of Enlightenment Antoine Barnave. The deputy of the Constituent Assembly over the period of 1789-1791, supporter of the constitutional monarchy, executed by the Jacobins, has lived his short life outstandingly, being an orator, a lawyer, a public character, and a scholar. The article is dedicated to the study of another little-studied part of his scientific legacy – the geopolitical views. The author conducts a comparative, historical, and typological analysis of the most well-known work of Antoine Barnave – “The Introduction to the French Revolution”. Examination of his scientific heritage allowed revealing that Barnave had implemented the methodology based on fundamental geopolitical dualism of the continental and maritime powers that in the XX century was acknowledged as the basic law of geopolitics far before Karl Haushofer and Mackinder Helford. Thus, the author makes a conclusion about Antoine Barnave as one of the first classics of geopolitics, as well as the earlier existence of the methodology of geopolitical analysis and geopolitical knowledge.