The author of this book is a historian of the revolutionary movement, publicist Vladimir Lvovich Burtsev (1862–1942), who emigrated from Bolshevik Russia in 1918. Before the revolution of 1917, V. L. Burtsev was engaged in exposing provocateurs in the Russian revolutionary movement, which allowed him in exile to write essays about the well-known world of provocateurs, enemies of the workers' revolutionary movement.