[The background, development and perspectives of modern epidemiology].

Epidemiology is an ongoing discipline (i.e. still being constructed) and many of the foundations of the theory and methods now in use were mostly developed during the second half of the twentieth century, arising from what is known today as "modern epidemiology". This paper summary the history and main ideas which guided epidemiology at that time, the debates and divisions that characterized such advance and presents a "biased" point of view concerning the perspectives which could help thinking about the disciplinary development of epidemiology.