The Menace of the Herd
Second, it is not by "Francis Stuart Campbell" but rather Erik Ritter von Kuehnelt-Leddihn.
Third, the author has to be one of the most impossible men of the 20th century: impossible in the sense that one almost can't believe a person like this existed. He seems more like an 17th or 18th or 19th century Euro- intellectual- aristocrat — dazzling knowledge of just about everything — than a writer from the 20th century. But there he was, and he left an amazing legacy in several books you can spend your whole life reading and learning from.
This is his most rare. It is an all-out attack on mob rule as the key to democratic totalitarianism. It is surely one of the most thorough-going anti-Nazi works ever written, especially because he understands the relationship between social and economic control (socialism) and the Nazi state. The book is not especially friendly to market economics, but it has other virtues: essentially the author does not believe that the state should make law, and he explains why. To read him is to experience something of an intellectual liberation from every sort of conventional wisdom, and yes there are some very un-PC parts of this book, but the reader should try to be as liberally minded as its author, and then we can all learn. I'm just so happy—we all are—that this book is back to life.