Now at Mark 24, the NAG C Library is a collection of hundreds of user-callable mathematical and statistical functions for C and C++ programmers. It contains over 1,500 powerful algorithms that are designed to be reliable, flexible and ready-for-use from a wide range of operating systems, languages, environments and packages, including Excel, Java, .NET, C# and VB. Extensions to the library have been made in many areas, namely statistics, optimization, linear algebra, ordinary differential equations, regression, random number generators and special functions, and include 148 new routines.