As you will very probably have already seen, The Open Logic Project (a team of serious and good people) has now made available an early public version of an open-source collaborative logic text, somewhat ploddingly called the Open Logic Text.
There are two things to comment on here (eventually!), namely the Text itself — or at any rate, the current snapshot of an evolving text — and the open-source nature of the enterprise.
At a first quick glance, the Text does look rather uneven: there are 77 pages on first-order logic and beyond (some at quite an elementary level), 100 pages on computability, incompleteness, etc. (this looks like a solid graduate course), and then just 21 pages on sets (at a very much lower level of sophistication). Still, this is obviously exactly the sort of thing that should be covered in the Teach Yourself Logic Study Guide. So when I’ve had a chance to take a serious look, I’ll report back with my two pennies’ worth, maybe in a mid-year update to the Guide.
You can download the current version as a PDF. But as the Project site says of the Text,
… you can download the LaTeX code. It is open: you’re free to change it whichever way you like, and share your changes. It is collaborative: a team of people is working on it, using the GitHub platform, and we welcome contributions and feedback.
I will be really interested to see how this pans out in practice. Using GitHub is a notch or three above my current nerdiness grade. But I simply don’t know if this is me just not keeping up with everyone — or whether it is pretty typical for logicians to know a smidgeon of very basic LaTeX, with that being about their geek limit. Maybe, at least as a bit of exercise to keep the brain from entirely rusting up, I should take a look at this GitHub malarky about which I’ve heard tell before (any useful pointers to an idiot’s guide?). Then I could also report back about how the collaborative aspect looks to a complete beginner. Again, watch this space.