  Underground laboratories provide the low radioactive background environment
necessary to explore the highest energy scales that cannot be reached with
accelerators, by searching for extremely rare phenomena. I have requested to
the Directors of the Laboratories a standard set of questions on the principal
characteristics of their laboratory and collected them in this compendium. I
included the ideas and plans for short-range developments. However,
next-generation structures, such as those for megaton-size detectors, are not
discussed. A short version of this work will be published in the Proccedings of
TAUP 2007.
