Hagai was born in Tel-Aviv October 14, 1928. to Yehuda and Esther,  Zionists at  Clausenberg  Transylvania, where  Orthodox Jewry was concentrated  persecuting Zionists. His father taught  at ‘Tarbut Hebrew High-School’   Hebrew linguistics, history of the people and Land of Israel. He immigrated to Israel alone 1925 and taught at Magdiel. His wife, and  children Naomi and Moshe arrived 1926. They resided in Sejera and Safed, and were saved during the 1929 riots by their Arab landlord, town mayor Tawafik Chuli. They moved to Ramat-Yishay and settled in Tel-Aviv 1931. Hagai studied at ‘Bilu’ School, in the ‘Aluma’ Yeshiva Jerusalem and  ‘Moria’ High-School Tel-Aviv (where he got expelled when underground activists were persecuted  by the mainstream populace). His parents house became a refuge for underground members in hiding, including some of the Latrun Prison escapees who influenced by him, and  beginning of 1944 he joined Lehi. He was active in the youth department, instruction, recruitment, publications and instructed courses. He wrote the pamphlets ‘The Target– the Enemy–The War’ and ‘Conspiracy’, which became manuals for new recruits. He was head of branches and cells. With establishment of the State, he joined  the IDF with other lehi members, as Division Commander in the 82^nd Battalion, 8^th Brigade, taking part in all the Brigade’s  battles. In the battle of Uja-el-Hafir, under heavy fire, Hagai rescued his friend Nechemya Ben-Tur, (injured from a shell hitting his armoured-vehicle) carrying him beyond the firing range. Eventually he chose his underground pseudonym Hagai as his first name. Active in the Fighters’Party  he was one of the heads of the Zionist-Socialist stream. He studied Orientalism at the Hebrew University, worked for ‘Davar’ newspaper Jerusalem as  political correspondent and  editor-in-chief.  He was  Davar’s London correspondent six years specialising in international political/strategic issues. He became  one of Israel’s leading correspondents publishing hundreds of articles which greatly influenced public opinion. His research regarding the ‘Lavon Affair’, commissioned by Ben-Gurion, was published as his book ‘Who Gave the Order?’, which shocked the public. He published  ‘Tomorrow is Now’ with Shimon Peres, and ‘A One Man Institution’, about Mossad founder Reuben Shiloach-Zaslani. Hagai passed away  November 18, 1988. His best articles were compiled in the book ‘Not only the Salty Heat’. He left behind  wife Aliza, and his two daughters Ariela and Ofra.