Much of C++ made more sense to me when I read Inside the C++ Object Model by Stanley Lippman[1]. It helped me internalize the fact that C++ was originally implemented as a preprocessor transformation into C (Stroustrup's Cfront). Thus many C++ mechanisms can be understood as elaborate syntactic sugar.

[1] http://www.amazon.com/Inside-Object-Model-Stanley-Lippman/dp...

It's very old and I have no idea how accurate it still is, but I found Inside the C++ Object Model by Stanley Lippman (http://www.amazon.com/Inside-Object-Model-Stanley-Lippman/dp...) to be tremendously useful in the mid-'90s for understanding what was going on under the hood.

Stroustrup's The Design and Evolution of C++ (http://www.amazon.com/Design-Evolution-C-Bjarne-Stroustrup/d...) is very good for explaining the "why" of C++, especially the stranger parts.

One other note, echoing some of the others: everyone picks out a subset of C++ and programs in that, and smart companies make that formal. You might see if your problem domain matches one of the available good ones, like Google's (well, I've heard that it's good).