Joe Valachi was the first one to reveal LCN to the rest of the world. Buscetta helped a great deal in the Maxi trails and the Pizza Connection trial. I have stated in another thread that Greg Scarpa Snr for the U.S. and Salvatore Contorno for the Sicilian mafia. Scarpa had been an informant since the 1960's till his death. Contorno became an informant when he went into hiding in 1981 after the Corleonesi killed his boss and most of his allies. As it has been stated in previous posts, the most damaging CI's are those that have been doing it for years and have not been caught.