This paper scrutinizes Bernays’s idea of propaganda demonstrated in his book Propaganda (1928), aiming at displaying the distinctive perspective and approach in the study of history of communication idea compared to those in the study of history of communication and history of communication studies. It further discussed the topics why Bernays deliberately advocated propaganda against the trend of his time as well as how he managed to legitimate propaganda by the proofs deducted from political theory and history of public relation. This study also finds that Bernays’s idea of propaganda was the natural outcome of American progressivism, which ultimately turned this movement against itself.