I suppose there is the inherent interest and entertainment of antique hardcore erotica for some people, which this book provides, but the things depicted (photographically) and described in this book may completely alter your view of the past.
I guess it is known that Berlin, prior to the rise of the nazis, was a decadant, burlesque place. But the variety and pervasiveness... and SEVERITY of this is not commonly known. In this book you will see gay nomadic boy scouts, theatrical spanking machines, nudist priests, gleefuly incestuous families (depicted in lifestyle journals for apparent mass consumption) and manuals of dentist chair molestation. It really is shocking - and all the more when you recognize these images as decisively in the past, and apparently NORMAL for this time period.
I used to look through this book whenever i went to this bookstore in 2000-2001, mostly browsing and skimming. It made a lasting impression and i have never been able to find similar information elsewhere. According to some of the reviews I've read, the author makes an unsubstantiated claim/conclusion that this period ended not because of social outrage or exhaustion, but because of particular economic and political circumstances. But for myself, foreign to this place and time (and culture), it completely changes my picture of germany, world war ii and modernity. Apparently there were sprawling nihilist fiends BEFORE mankind was confronted with the possability of nuclear annihilation.
I personally consider this a "coffee table book", albeit for S&M yuppies. It is way too flashy and consumable for research purposes. (I would hesitate to site it as a source for any paper.) However, as far as I can tell, it is one of the only accessable documentations of ...something I can't believe I've never heard of.