The Devil's Lieutenant by M. Fagyas
Published by Putnam on June 1970
Len's Summary: A murder mystery featuring the Austro-Hungarian officer corps in 1910 Vienna and elsewhere in the ramshackle, multinational and polyglot Habsburg Empire. Intrigue in the Imperial and Royal Army as Austria-Hungary stumbles toward war. A fast-paced and finely crafted fictionalized glimpse of a decaying Empire written by the daughter of an imperial officer.