Another camera, and you're fine. >> I don't know. >> Is it working? >> Is it working? >> It's working. >> Are you selfieing? >> Yeah, this is my selfie cam. My Gimbal selfie cam. >> It works great. >> Yeah. So this way, I can tape my meeting of Allen Downey. >> Sweet. >> That's gonna be sweet. >> The moments. >> The moment that I meet Allen. >> That's how helpful. >> It is. >> Very cool indeed actually. [LAUGH] >> Folks, that's Allen Downey, who started the whole Think Java, Think Python, revolution back 1999 and I'm gonna meet him now. For the first time. >> And you can ask him that question, that I should have asked him a long time ago. Right? >> So what are your thoughts, Jeff? Right before we meet the great Allen Downey? >> I'm excited, I'm excited, I'm excited. >> Okay. >> [LAUGH] >> It's very exciting, but you've met Allen before. >> I have, I have. >> This is my first time. >> But it's always exciting. >> Exactly >> [LAUGH >> Hi. >> It's Allen Downey. >> [LAUGH] >> I'm Charles Severance. >> Charles, it's great to see you. >> We're co-authors. >> Yes. >> We've never met in person. We talked on the phone. This is the famous Jeff Elkner of course. >> I'm thrilled. Jeff, it's nice to meet you. >> Made famous by this guy. >> [LAUGH] Yeah, well we all, everybody got made famous. >> That's right. >> So the first question I was asking Jeff, and he doesn't even know the answer to. Is why did you choose GFDL back in 1999? That was before creative commons, before OCW. Before everything. >> Yeah. >> What possessed you? >> You know actually the first version of the book I put it under the Gnu three. >> GFDL? >> No, not. >> GPL >> The GPL. >> Oh, you did GPL? >> Because I didn't even know about the FTL. >> And then somebody got a hold of you from MIT. >> And they said, wait a minute, this is documentation, this is not code. You should have used this other license and so I switched. And then when Creative Commons came along, some of those licenses have been useful. >> Yep. >> Actually part of the reason that working with O'Reilly has worked out very well. >> Yeah. >> I do things usually under a non commercial >> Yeah. >> Creative Commons license. And then that's kind of a compromise. >> Yep. >> It's maybe not ideal. >> But those are the details the why questions. >> No the non-commercial's I think a beautiful thing >> Yeah. >> And actually Creative Commons is thinking about getting rid of it. I'm sad about that, because I think it's a fine middle ground, for e-copies can be delivered free and no one feels bad about that. Print copies you make money off of so it's pretty cool. >> I agree. I think there's a nice huge case for it. >> So have you ever tried to count the number of derivative books of Think Python? >> No. >> Do you think it's 100, 200, 300? >> I don't think it's 100. >> How to think like a computer scientist, Java version. The original. >> If you go all the way back. Yeah, all the way. >> Java's the original. There are a number of English language books that are modified versions. >> Including mine. >> There are also- yep. >> We need to get that data. >> There are translations into other languages. >> I count those as separate ones. >> Yep. >> But like Runestone like Brad Miller's stuff. >> But then there's the interactive one. >> The interactive ones, yes. >> And then his book now. >> Do you have an interactive version? >> No, no, no, I just have the Python for Informatics print and e-version. >> Yeah, but that's been out for a while. >> Yeah. >> I did that many years ago. And then I fought with Cambridge Press, remember that? >> Yes. >> Remember those calls? So but why did you give it away? I mean it wasn't so cool in 1999 just to give books away. It was not normal. >> True, no. >> That's the question I had. >> Can we pause? I do wanna, I wanna finish signing books so these folks are- >> Okay, so we'll have to talk later. >> Okay, okay, we'll get back to this. >> Let's talk more.