Many people find their way to my site, interestingly enough, because of the research work done by my mother, Barbara Lottinger Allen. Her book on the Falgout family does serve as an invaluable resource for anyone in that lineage and is exhaustive in its breadth.
It’s currently not in print. Plans are in the works for it to be reprinted on-demand, and hopefully within a year (or two) that will be realized. It’s just me here with scanner, after all. And boxes of research notes, which several people have asked for.
Feel free to be in touch. I’m not hard to find.