Harry Lask, son of Jacob, was born in Riga, Latvia July 30^th, 1909. In Riga he joined the Beitar movement, and in France he was a fighter in the French Resistance and a captain in the Foreign Legion, was wounded and his hearing was impaired. In January 1947, he joined the Lehi in Paris. He was an Electric engineer and had a head full of ideas. He established a workshop in Paris where he assembled explosives for use in Lehi. He operated in the Technical Division and was considered an expert of explosives and suspended release mechanisms. He participated in the planning and preparation of bombs to be sent to England as well as preparing 70 explosive envelopes, while risking detonation in the laboratory. His recruiter and commander in Paris was Herzl Amikam. He received the Lehi badge.