Pasadena: Published by the Author, (1920). 1st pb edition (Ahouse A27a; Baird & Greenwood 2268). 329,  pp. No printed note. 5 pp of adverts at rear. Printed on kraft paper. 12mo. 6-13/16" x 4-3/4". Buff printed wrappers. Age-toning. Faint stain to upper left of front cover. A solid VG copy. Item #28166.1
Per B & G, the work "based on the Mooney-Billings case, otherwise known as The Preparedness Day Parade Bombing, San Francisco, July 22, 1916. Both Mooney and Billings were convicted (Sinclair felt unjustly), and when he ran for Governor of California in 1934 he pledged to pardon both men if elected."