TITLE: Beginning reference for configuration spaces
QUESTION [11 upvotes]: In my mathematical reading and thoughts, I keep running across the notion of configuration spaces, and while I essentially understand the idea behind them, I don't have much intuition for them (not even simple ones like the configuration space of two (indistinguishable) points on a line), and I don't know how computations are done with them. Is there a textbook or paper that would serve as a gentle introduction to configuration spaces, to someone with perhaps a semester of graduate algebraic topology (or maybe a little more?)

REPLY [3 votes]: Let me add one more introductory book.
Hansen, Vagn Lundsgaard. Braids and coverings: selected topics. With appendices by Lars Gæde and Hugh R. Morton. London Mathematical Society Student Texts, 18. Cambridge University Press, Cambridge, 1989. x+191 pp. ISBN: 0-521-38479-6 MR1247697
If I remember correctly, this small book does not require much and explains basic techniques to handle configuration spaces of manifolds, such as the fibration sequence given by selecting points.
Note, however, that most classical books and papers, including this book and the one by Fadell and Husseini, only deal with configuration spaces of manifolds. In order to study configurations spaces of singular spaces, we need completely different techniques.
For example, a graph $\Gamma$, regarded as a 1-dimensional cell complex, is a singular space. We cannot use the basic fibration technique. I recommend this expository article by Abrams and Ghrist for such configuration spaces.