Introduction to discrete subgroups of the euclidean group I am looking for a general introduction to discrete subgroups of the euclidean group (= group of isometries in euclidean space).
Even though I searched quite a bit, I was unable to find a good introduction.
Any hints for which book or survey to look?

If you are interested in dimensions 2 and 3, consider reading "Geometries and Groups" by Nikulin and Shafarevich. 
If you are interested in higher dimensional groups as well, Wolf's "Spaces of constant curvature," covers basics (and much more). 
