Welcome to the catch-all "Miscellany" chapter. There are only three Items here, but don't let their diminutive number or unglamorous setting fool you. They're important.
The first Item emphasizes that compiler warnings are not to be trifled with, at least not if you want your software to behave properly. The second offers an overview of the contents of the standard C++ library, including the significant new functionality being introduced in TR1. Finally, the last Item provides an overview of Boost, arguably the most important general-purpose C++-related web site. Trying to write effective C++ software without the information in these Items is, at best, an uphill battle.