MRCS LRCP 1940.
Klass was born in Manchester on 17 September 1914. He studied at North Manchester High School and the University of Manchester. After qualifying, Klass held positions as house surgeon and junior medical officer at Southport Emergency Hospital and was then senior house physician at Stepping Hill Hospital, Stockport, before settling in general practice in Salford. Klass was a fellow of MMS and medical officer to Manchester Jewish Lads Brigade. Klass was also justice of the peace for Salford and vice-president of Salford Liberal Party. His son, Howard Julian Klass, was also a medical practitioner in Manchester (see above).