Their theory on the Black Hand has stood the test of time, being generally accepted today by Mafia writers. Although the terms "Black Hand," "Mafia," "Camorra," and related terms are often conflated, Pitkin and Cordasco show through news items, contemporary experts' usage of the terms, and the details of the crimes and criminals involved, that Black Hand was not an organization but an extortion phenomenon that began in 1903 with a New York City newspaper report of extortion in Brooklyn. The movement quickly caught the imaginations of readers and criminals of all stripes, and was the scourge of the 1900-1910s in Italian communities. Black Hand faded from the newspapers when it was eclipsed by the possibilities opened to criminals by Prohibition in 1920.
This is one of the better books available on the subject. Many of their observations have been demonstrated in Critchley's book on the American Mafia. This book is also well documented, a characteristic sorely lacking in many mob books.