This paper deals with Kantian philosophy and its evolution in the history of ideas. It reveals a set of philosophical concepts that emerged post Kant and that revolved around the interpretation of his texts and drew inspiration from his principles. Neo-Kantians advocated the need "to return to Kant" in order to understand the times and raised the dilemma of what exactly was meant by this slogan and its implications for those who promoted it. What does the return to Kant mean? Is there a single defined form of this return or did it take various and conflicting forms? In other words, how did the neo-Kantians interpret Kantian philosophy? Did they remain faithful to Kant or did they propose readings that differed from his thinking? Was their work limited to reclaiming and imitating his ideas literally or did they renew and expand the horizon? To address these challenges modern philosophers with a neo-Kantian outlook are here revisited, specifically Wilhelm Windelband and Heinrich Rickert of the Baden school, as well as Hermann Cohen, Paul Natorp, and Ernst Cassirer of the Marburg school. The paper suggests that Kantian philosophy has been differently perceived, and that neo-Kantians were inspired by Kant's philosophical method rather than his ideas as a whole. Neo-Kantianism is not a school of faithful adepts or blind followers of Kantian texts. On the contrary, it includes divergent readings and puts forward various interpretations of these texts. The neo-Kantians have worked to interpret the philosophy of critique in different modes and critiqued and revised it in light of modern developments in science and philosophy. This has allowed this philosophy to develop more and more, thus maintaining its openness and relevance.