Explain STL

I have been working on C++ for the last tw months. I have found it very easy to understand and code. But recently I am stuck on a topic - STL. What exactly is STL ? I have no clue about this. I have read my C++ book but there is not much mentioned about it. Can anyone explain it to me ?

Yes, it is not that commonly known to all C++ begginner as to what exactly STL is. STL stands for Standard Template Library. The Standard Library is a fundamental part of the C++ Standard. The C++ Standard Template Library is a generic collection of class templates and algorithms that permits developers to easily implement standard data structures like lists, stacks and queues. It is said to provide iterations, functors, containers and algorithms. This C++ STL is derived from STL published by Silicon Graphic Inc.

An already existing set of common classes for C++ is provided by the C++ Standard Library - STL(Standard Template Library). It is a library that constains container classes, iterators and algorithms to work with the contents of these containers. Algorithms of STL are not dependent on containers, which thus reduces the complexity of the library to a great extent.

The Standard Template Libraries i.e. STL are a set of C++ template classes which provide common programming data structures and functions such as paired arrays (map), doubly linked lists (list), large string storage, expandable arrays (vector) and manipulation (rope), etc. There are two types of STL containers in C++:
Sequence Containers- C++ Vectors, C++ Lists and C++ Double-Ended Queues.
Associative Containers- C++ Maps, C++ Multimaps, C++ Sets, C++ Multisets.