Yaacov was born in Lisichensk Russia, on September 5,1917 to Yerachmiel and Batya, Zionists who taught him Hebrew and prepared him for Aliya. They made Aliya and settled in Tel-Aviv 1924. Yaacov studied at ‘Echad-Ha’am’ school and ‘Herzliya High-School’. Aged 15  he joined the ‘National Cells’, then National Defence and participated in anti-British demonstrations . Completing studies, he was accepted to a command-course in Poland. In 1939 he was put in charge of activities in Jerusalem and arrested with other Etzel Commanders August 13,1939. When Etzel split, he joined Yair and was responsible for the North. In 1941 he was appointed head of Planning &Instruction.  On January 27,1942 he was injured by the British on 30 Dizengof St., arrested, and sentenced to life. After Yair’s assassination, he believed all Jewish undergrounds  should  unite in their battle against the British. On December 24,1943 he escaped from Jerusalem Prison, and contacted Hagannah representatives regarding co-operation. He commanded Lehi’s Fighting sector and represented Lehi in the Freedom Movement’s Command. In 1946 he was sent to Egypt for operational planning. End of 1946 he became Operations Chief in Europe, relocating to Paris. Among his operations:  planting a warning mine at the Colonies Ministry, envelope bombs to selected government officials, and more. He was arrested on the Belgian border, sentenced to eight months’ prison. Returning to Israel during the War of Independence he became deputy commander of the 89^th Battalion, 8th Brigade. He participated in the conquest of Beit-Govrin, Lachish, Dweima, Iraq-Souidan police, liberating the road to the Negev,  Operation ‘Chorev’ and the conquest of Uja-el-Hafir. He was Battalion Commander with Golani Brigade and served in the IDF until 1953. Yaacov married Hanna Musayeff; they had two daughters, a son, and grandchildren. In 1955 he was sent to Europe on a state-security mission. On return, he headed security at Bank of Israel.  Among the founders of ‘Brinks Israel Ltd’, he was its president from 1965-76. Yaacov had a Masters in chemistry from the British Institute and graduated  Political Science from Hebrew University. He published a biographical book, ‘Wanted’. Yaacov passed away February 25,1985.