From the Letters of Note blog:

Early-1971, in an effort to attract as many youngsters to the premises as possible, Marguerite Hart — children’s librarian at the newly-opened public library in Troy, Michigan — wrote to a number of notable people with a request: to reply with a congratulatory letter, addressed to the children of Troy, in which the benefits of visiting such a library were explained in some form. It’s heartening to know that an impressive 97 people did exactly that, and below are just four of those replies, all from authors: Isaac Asimov; Hardie Gramatky; Theodore Geisel; and E. B. White.

(Although sadly a common situation these days, it’s worth noting that Troy Public Library is currently dodging closure. How long it remains open is a mystery.)

It’s fascinating to read all the letters which Ms. Hart received. The Troy Library has put all of them online for you to read. In particular, I love this quote from Neil Armstrong’s letter (PDF), which I think not only applies to libraries, but to the sharing of knowledge that goes on here at Adafruit, and with open-source in general:

All of this knowledge is yours for the taking. It is something you will have always and that will grow in sharing.

Knowledge is fundamental to all human achievement and progress. It is both the key and the quest that advances mankind. The search for knowledge is what brought men to the moon; but it took knowledge already acquired to make it possible to get there.

Truth.