Learn to program in 21 days (comic)
abstrusegoose.com
abstrusegoose.com
10 years later it is worst than your nightmares.
Just because I know Java + Ruby Syntax + Some stuff on RoR does not mean I am a good RoR programmer, there's just so much more to RoR than the syntax.
I want to see someone completely grok pointer logic in 24 hrs from knowing nothing.
Depends on what exactly "reading" encompasses. If you can work through a good book (say SICP) doing all the exercises etc and writing a lot of code, I'd be very surprised if you don't "level up" very fast. If you've worked completely through "C Interfaces and Implementations" by David Hanson, you should be a pretty good C programmer at the end.
Working through a series of great books will amplify this effect.
so yes you can achieve a lot through proper use of books but 21 days, no way.
Math may be the one of the few areas, where this is true. If you can read (and understand!) a math book, you have already gone pretty far. But that's much closer to reading source code (or poetry) than your average book.