Case histories form a substantial element of the medical literature. However, due to their inherent anecdotal and observational nature, the description of an individual patient report is hardly considered to contribute to evidence-based medicine. For these reasons, some journals even exclude case histories from publication. Is this a good policy? In my opinion, on the contrary! Case histories can be the true background for systematic or hypothesis-based research. The accurate observation and description of a single patient case may form the basis for further exploration of the observed phenomenon, thus opening new fields of interest. The role of case histories is therefore to expand our knowledge based on incidental experiences. The first clues about tobacco smoking and lung cancer came from surgical patient series in the 1920s and 1930s; formal case-control and cohort studies came only decades later.