The libraries that come with the .NET Framework are large, and cover almost every task programmers are likely to tackle. Using them can save programmers hours or days of work.
The same class libraries are used in Visual Basic, C#, and managed C++, but managed C++ can also call some unmanaged libraries that Visual Basic and C# cannot access.
The System namespace holds classes for simple common tasks, and a large number of sub-namespaces for slightly less common (but still important) tasks , including string manipulation, IO, and threading.
