- "'A study of Hogwarts prefects and their later careers', Ron read aloud off the back cover. 'That sounds fascinating...'"
- —Percy Weasley's reading choice[src]
Prefects Who Gained Power was a study, published in the form of a book, about successful prefects at Hogwarts School of Witchcraft and Wizardry and the career paths they followed after leaving school. It was a very small book, and was frequently described as being deeply boring.
One edition of the study was published sometime prior to August 1992; Percy Weasley read a copy of this while visiting a junk shop in that year, for which his brother Ron and their friend Harry Potter mocked him.
Following Percy's success in the Ministry of Magic, ending up as the Head of the Department of Magical Transportation, the author of this study inducted him into the list of prefects covered, and offered a short biography of him.