Downloadable Air Defense Study (German language only)

[HPL2008]

Searching for info on the SHD, I stumbled upon this interesting free publication (no bootleg, by the way; it is an official German Government download):

BBK Hampe Der zivile Luftschutz im zweiten Weltkrieg

Originally published in 1963, its author was none other than Erich Hampe, the former deputy head of the TN.
This is a thorough 600+ pages study about the civilian air defense system in WW2 Germany covering all areas from the SHD and LSW to the Werkluftschutz and even the Railway- and Postal Air Defense Services. (Please note that this is not about uniforms and insignia, but about the history and organisation of these services.)

German language only, but I thought it should share this for the benefit of the German-speaking members.