Perilous is the thirteenth studio album by American progressive rock band Glass Hammer, released on October 23, 2012 by Arion Records/Sound Resources.This is the last album with Jon Davison acting as sole lead vocalist, with former vocalists Susie Bogdanowicz and Carl Groves returning on the following album. It is also noteworthy to note that the song titles, when read in sequence, form a kind of poem. It is the first album featuring Davison in which he was not actively involved into the songwriting process, as he joined Yes previously in the year and was not available for the songwriting sessions.As some previous albums like Journey of the Dunadan or Chronometree, Perilous is a concept album. However band member Steve Babb stated "we have never done a concept album like Perilous. It is essentially one unified vision; one musical idea in thirteen parts or movements. The emotions and ideas expressed in the lyrics ebb and flow with the music; but they have a definite story to tell with a beginning, middle and climactic end."