The Who Was/ Who Is books are short biographies of inspirational figures aimed at middle-grades readers. They make use of frequent illustrations, diagrams, and interludes as well as lively, concise text to encourage engagement. These biographies are written by many different authors, although some writers—like Roberta Edwards—have contributed several times to the series. The series began in 2002 and since then more than 250 books have been published. The series has been so successful for Penguin that the publisher has added two similar lines, the What Was? and Where Is? books that discuss places, events and objects of historical significance. Penguin’s site dedicated to this series, Who HQ, explains that the subjects of their biographies are “People who are the first at something, or the best at what they do, or who have made major contributions in their field.”

The books in this series are titled with the words “Who Is” for living subjects and “Who Was” for deceased subjects. When a person profiled in a “Who Is” title passes away, subsequent editions of their biography are retitled with “Who Was.” For instance, before Neil Armstrong’s 2012 death, all editions of Edwards’s biography of Armstrong were titled Who Is Neil Armstrong? After Armstrong’s death, the title and its contents were updated to reflect Armstrong’s passing, and the book is now called Who Was Neil Armstrong?