The h-index is a mainstream bibliometric indicator, since it is widely used in academia, research management and research policy. While its advantages have been highlighted, such as its simple calculation, it has also received widespread criticism. The criticism is mainly based on the negative effects it may have on scholars, when the index is used to describe the quality of a scholar. The "h" means "highly-cited" and "high achievement", and should not be confused with the last name of its inventor, Hirsch. Put simply, the h-index combines a measure of quantity and impact in a single indicator. Several initiatives try to provide alternatives to the h-index to counter some of its shortcomings.