Questions, remarks and error messages concerning this tutorial are always welcome. A work like this is never really completed; rather it is permanently being improved. The author is therefore pleased about every mail to <ziegler@mpi-sb.mpg.de> with the word “LEDATUTORIAL” in the subject line and will try to incorporate every reasonable suggestion into the text sooner or later.

It be pointed out again that every reader who makes a contribution to this tutorial, however marginal it may be, will be mentioned by name in the acknowledgement!

The respectively most current version of this tutorial is found on the web page of the online version. An errata list can also be found there.

Smart solutions to exercises should be sent to the author; these will be published on a web page of their own.