This entire comic is free to read and share, under Creative Commons licensing. There are a lot of reasons we presented it this way, but it's mostly because we want as many people as possible to enjoy it. Writers and artists need to make money, but paywalls are stupid and evil and no fun.
If you think this was the right way to go, please show your support by dropping a little something in the tip jar.Any tip will get you a full .pdf copy of the comic, plus the original 4000-word story by Ben Bova. Tipping $10 or more will get you a copy of the big and beautiful physical book (8 1/2" by 11" full color), postage and handling included! ($13 or more outside North America). Top contributor before midnight September 30, 2010 will also get the unique misprinted proof, with a missing page and a duplicated page, signed by all three creators.