The Obolus Press specializes in monographs about French and German painters, mostly but not exclusively from the Belle Époque and the early Modernist era. From time to time the press will also venture into history, philosophy, and literature from the same periods.
The publisher has recently decided to sever ties with third-party distributors in general, and with Amazon in particular (read more). You may still find Obolus titles on other sites, but they tend to be ridiculously overpriced. Save money and support a small press by ordering directly.