Charles Darwin's personal letters have a reputation for being quite revealing, and, at times, very entertaining. They're where he weighed the pros and cons of marriage, and berated himself for being "very stupid." Now, more than 1,000 letters between Darwin and botanist Joseph Dalton Hooker have been made available free …

It's easy to forget that our Latin-derived alphabet came from earlier alphabets that used physical objects to represent their letters. Cartoonist Jason Novak reminds us of the Egyptian, Phoenician, and Sumerian origins of our modern alphabet, with the letters incorporated into sketchy, energetic cartoons.

Even the great masters of science fiction paid tribute to the people who influenced them. Today, Letters of Note has a beautiful 1976 letter that Ray Bradbury wrote — by hand — to Robert Heinlein.

After the first pilot for Star Trek was on the verge being rejected by NBC, Gene Roddenberry sent this impassioned letter to his agent on February 12, 1965. It's a fascinating snapshot of Roddenberry with his back against the wall.

A 1973 letter from Star Trek creator Gene Roddenberry to a fan is worth reading. He explains that Trek had no "magic formula" other than focusing on people. And Spock looked like the Devil because it was "provocative to women."

Author Robert Heinlein took great pride in his military service, having graduated from Annapolis and served in the Navy. In a letter to fandom leader Forrest J. Ackerman, Heinlein condemns science fiction fans who didn't participate in WWII efforts.

Philip K. Dick died before Blade Runner was completed, but in a letter to film's production company, he praised what he'd seen and claimed it would breathe life into what he believed was a stale genre. [via Letters of Note]