Framework vs. Library

I remember that there was no clear answer to this question. Today I saw a piece of Martin Fowler's text, which makes sense. record it.

Inversion of control is a key part of what makes a framework
Different to a library. A library is essential a set of functions
That you can call, these days usually organized into classes. Each
Call does some work and returns control to the client.

A framework embodies some abstract design, with more behavior
Built in. In order to use it you need to insert your behavior
Various places in the framework either by subclassing or by plugging
In your own classes. The Framework's code then callyour code
These points.

From: http://martinfowler.com/bliki/InversionOfControl.html