Stroustrup, Bjarne. The Design and Evolution of C++. Reading, MA, USA: Addison-Wesley, 1994. ISBN: 0201543303
Bjarne's no nonsense explaination of how C++ came to be is interesting. It makes you understand where the weaknesses in the C++ programming language came from, and makes you realize what some of the strengths are. Fascinating reading for anyone deeply involved with C++.