A pretty rarified accomplishment

Harper Lee pass away today. She was famed for her authorship of To Kill a Mockingbird, her sole book till the publication of an early version of TKAM in the last couple of years.

The book is wonderful storytelling of a complicated and fraught period of American history and it is a wonderful book which is enjoyed by adults, children and people from all walks of life. It is commonly assigned in school as either required or recommended reading.

It is hard to measure the quality and popularity of books. According to Pantheon database of globally consequential people, Harper Lee is 144 in the list of all American authors. Hers is the 38th most commonly assigned text among college students.

According to the New York Times, there have been more than 40 million copies sold of To Kill a Mockingbird.

It is rare that even 10% of children in an age cohort will have read a common book by a particular point in time. The most commonly read book of which I am aware is the picture book Goodnight Moon by Margaret Wise Brown. First published in 1947 it has never been out of print and still is one of the highest selling books in any given year, selling some 750,000 copies each year. Given that there are roughly 4,000,000 in each annual age cohort, the implication is that roughly 19% of each age cohort has been read Goodnight Moon. That probably understates her influence. A family might buy only a single copy and yet have more than a single child.

What about To Kill a Mockingbird? The New York Times indicates that 40,000,000 copies have been sold since it was first published in 1960. That's 56 years which yields a total age cohort of (56 X 4,000,000) 224 million. 40/224 is 18%. Not bad staying power and penetration. That's pretty rarified.