Sir Martin Gilbert, who has died aged 78, was a distinguished historian and the official biographer of Winston Churchill.
The author of more than 80 history books and atlases, he often wrote on Jewish themes and was a committed Zionist, though quietly critical of today's Israel and of the dominance of the Likud party.
He was as interested in geography as in history and his many historical atlases are strikingly original and have often been imitated.
An early work, The Appeasers, caught the eye of Randolph Churchill, who was working on a biography of his father, and in 1962 he asked Gilbert to join his small team of researchers at his country retreat at East Bergholt, Suffolk.
When Randolph died in 1968, with only two volumes completed, several contenders put themselves forward to continue the work, including Randolph’s son, Winston, and Robert Rhodes James, a historian and Conservative MP.
But the publishers thought Gilbert was the only candidate with the knowledge and energy sufficient to carry the project through to a successful conclusion.
Gilbert saw himself as a chronicler, carving a historical narrative from the documents and the archives, and allowing readers to make their own judgments. He was a master of detail but his particular genius, at first with Churchill and later with books on the Holocaust, was to bring into his books as many ordinary people as he could.
The son of Peter and Miriam Gilbert, he was born into a Jewish family in north London. His sister, Margaret, became a philosopher of sociology. Their father was a jeweller in Hatton Garden.
Gilbert was brought up in the Jewish faith, and his faith became stronger as the years passed, encouraged by his close friendship with Rabbi Hugo Gryn.
Educated first at Highgate school, he won a scholarship to Magdalen College, Oxford, where he fell under the spell of the historian AJP Taylor.
After Churchill, the second theme of Gilbert's life's work was the Holocaust. He had visited many of the concentration camps sited in occupied Poland as a student, and a concern with the story of the Jews of central Europe and Russia led to a fresh stream of works about Israel and Jerusalem, including Auschwitz and the Allies (1981), an account of the allied failure to respond to news of the death camps, and his magnum opus, The Holocaust: The Jewish Tragedy (1986). Amiable His huge knowledge of history and his considerable amiability, gave Gilbert easy access to successive prime ministers. He was a frequent visitor to Downing Street and helped Harold Wilson with his memoirs. He had little time for Margaret Thatcher or Tony Blair, but was close to Gordon Brown and also friendly with John Major.
He is survived by his third wife, Esther Goldberg, whom he married in 2005 and by a daughter, Natalie and two sons, David and Joshua, from two previous marriages which ended in divorce.