This is a huge library of c routines to do just about anything. The only sore spots are some of the vector and matrix routines. They are divided up so that some very simple operations require several routines. Of course this was done for flexibility, but some may find that writing their own is more efficient. Also, the two point boundary value problem solvers are very limited and the DE section only contains constant time-step solvers. The special function section is excellent, however. Nevertheless, despite the limitations, I have found this to be a gold mine of routines and an extremely useful book. I can often find stuff here that is almost impossible to find elsewhere.