There is a huge literature on object-oriented programming in general and C++ in particular. Our favorite reference is Stanley Lippman's C++ Primer published by Addison-Wesley. A comprehensive introduction to optimization is Roger Fletcher's Practical Methods of Optimization published by Wiley. In the context of inverse problems, most of the algorithms in COOOL are described in Introductory Geophysical Inverse Theory by John Scales and Martin Smith. This book is freely available via Internet from Samizdat Press; for more information send a blank email message to
samizdat@dix.mines.eduor point your WWW browser to
http://landau.mines.edu/~samizdatand follow the directions.
The Stanford Exploration Project has been among the pioneers in the use of C++ in geophysics. Their excellent ``Programming Geophysics in C++'' is available from the SEP WWW site at the
http://sepwww.stanford.edu
There are also a large number of freely available C++ class libraries. A good source of information is Netlib, accessible via the WWW at the address
http://www.netlib.org