Evan:

If I try learning C, then I could go directly to K&R or even pick up a modern Dummies book, but for period's sake it would be the former.

But remember the intended audience back then. K&R was BY computer folks FOR computer folks. It's "concise", thus all the followup annotated versions by others. Computer centers had a social element: the local guru instead of Google and wikis. AT&T, colleges all had formal & informal heirarchies of staff & helpers to help newcomers. You cannot assume such an environment anymore, an issue Kernighan and I discussed at VCF. Referring to Grace Hopper's interview on David Letterman: there were no manuals for the ENIAC. It was all learn by the seat of your pants. Writing manuals was quite the cottage industry, thus all the "learn along with us" newsletters, user groups and magazines. The Beagle Brothers were legendary for their fun Apple tips & tricks. O'Reilly Nutshell books set the standard for how to learn new things QUICK.