The decisive fact of the 19th century, as Bismarck recognized, was that Britain and the United States spoke the same language. Addressing Congress in 1952, Winston Churchill urged, "Let us be sure that the supreme fact of the twentieth century is that they tread the same path." Throughout his career, Churchill promoted the congruent interests of the two great English-speaking democracies. When he was minister of munitions in 1917, he said there were only two ways left to win the war: "one is aeroplanes and the other is America." In 1955, upon his retirement, his final advice to his colleagues was "never be separated from the Americans." The Anglo-American relationship in Iraq and elsewhere shows the continued vitality of the alliance.

Churchill and Roosevelt cemented the ties between their nations and profoundly influenced the outcome of World War II and its aftermath. Between 1939 and 1945, when FDR died, the pair exchanged nearly 2,000 letters. From August 1941 through February 1945, they spent a remarkable 113 days together. One result of this close relationship was that Churchill dissuaded FDR from invading Western Europe in 1942 or at least 1943. Such a premature assault could easily have produced a disastrously prolonged war. France, all Germany and a good part of Western Europe would then have been liberated by the Red Army.

In Franklin and Winston (Random House, $ 29.95), Jon Meacham, the managing editor of Newsweek, focuses tightly on what the two leaders "meant to each other -- and, in the end to all of us." He relies primarily on the voluminous printed record while effectively utilizing his own interviews. He also successfully draws on previously unavailable or neglected material, such as letters to Pamela Churchill Harriman from various participants at the wartime conferences.

With its keen, nuanced analysis and sympathetic insight, Meacham's book makes for intense and compelling reading. His achievement is memorable, even considering the innate drama of his topic. His heroes are charismatic giants, paladins in a titanic struggle between good and evil, and masters of the English language and the theatric moment.

Few dramatists could match the poignant scene when Britain stood alone against the Nazi power that dominated a conquered or fawningly neutral Europe. Roosevelt sent his envoy Harry Hopkins to Churchill. At dinner Hopkins quoted from the Book of Ruth: "Whither thou goest, I will go; and where thou lodgest, I will lodge: thy people shall be my people and their God my God," softly adding, "Even to the end." Another moving episode was the secret August 1940 meeting of the still-neutral Roosevelt and Churchill, off Canada, on the British battleship Prince of Wales. Roosevelt walked painfully, supported by his son, determined not to use his wheelchair. At the Sunday service, the commanders and the crew sang, "Onward, Christian soldiers, marching as to war." Within three months, the Japanese sank the Prince of Wales.

Churchill was in the Oval Office in mid-1942 when the president received a cable. The 25,000-man British garrison at Tobruk had surrendered to half that number of Germans, jeopardizing the entire Middle East. The prime minister made no attempt to hide his shock at what he felt was a disgrace. FDR asked, "What can we do to help?" Churchill requested the shipping of as many Sherman tanks as could be spared to the Middle East, as quickly as possible. Although U.S. armored divisions needed the tanks to replace their own obsolete ones, Roosevelt issued the order immediately.

The two leaders were strikingly different. Churchill was a romantic whose relationships were usually spontaneous, open and generous. As his daughter Mary observed, "He could be wily if he had to, but it did not come naturally." Deviousness came naturally to Roosevelt. Despite his warm public persona, his successor, President Harry S. Truman, described him as "the coldest man I ever met. . . . He didn't give a damn personally for me or you or anyone else in the world as far as I could see." Eleanor Roosevelt wrote, "A man in high public office is neither husband nor father nor friend in the commonly accepted sense of the words."

Yet it is undoubtedly true that, despite occasional fraught episodes, in the colloquial sense Roosevelt and Churchill became close friends. Roosevelt was not feigning when he told Churchill, "It is fun to be in the same decade with you." Once, in Egypt, watching Roosevelt try to stand, Churchill turned to his daughter, Sarah, his eyes bright with tears and said, "I love that man." Even Eleanor spoke of their reciprocal affection. Churchill's greatest contribution was to keep Britain fighting the war without allies. The theme of his second volume on the war was "How the British people held the fort ALONE till those who had hitherto been half blind were half ready." Roosevelt's decision to furnish materiel to Britain under the Lend-Lease Act was vital. Before Pearl Harbor, Churchill knew that his only hope of victory was to "drag the United States in" to war. Churchill admitted, "No lover ever studied the whims of his mistress as I did those of President Roosevelt."

For his part, FDR did his best to convince Hopkins that the danger of a full-scale German invasion of England was imminent, even though British code breakers knew otherwise. Although Meacham does not mention it, British intelligence supplied the Americans with forged documentation of Hitler's supposed efforts in South America, material that found its way into a presidential speech. British codebreakers read America's secret codes, at least until Pearl Harbor. In wartime, the traditional mandates of friendship, such as telling the truth, can stop at the water's edge.

For more than a century, the Churchills have been writing history, usually about their ancestors. A sampling includes Winston's 1906 two-volume biography of his father, Lord Randolph, and four later volumes on John Churchill, the first duke of Marlborough. Winston's son, Randolph, wrote the first two volumes of the eight-volume life of his father, which was completed by Sir Martin Gilbert. Randolph's son, Winston, penned the life of his father.

The flow continues. Mary Soames, Churchill's youngest and only surviving child, has revised and updated her outstanding and astonishingly objective biography of her mother, Clementine Churchill (Mariner; paperback, $ 18). She grapples inconclusively with the identification of her mother's biological father. Responding to a question as to how her father had accomplished so much -- politics, writing, painting, even bricklaying -- her mother replied that Winston "never did anything he didn't want to do, and left someone else to clean up the mess afterwards." It might have been more accurate had Clementine replied (as she never would have) "because I am his anchor." When Churchill became impossibly overbearing to his colleagues, she was capable of telling him in writing that he would not get the best results by "irascibility & rudeness," which would "breed either dislike or a slave mentality." Although she devoted her life to Winston, during World War II Clementine agreed not to tell him that increased flying could cause a heart attack. Their daughter's contribution to Churchillian literature is indispensable.

In Chasing Churchill (Carroll & Graf, $ 25) Churchill's granddaughter Celia Sandys, who previously penned a fine book on Winston's exploits during the Boer War, now uses the gimmick of retracing his travels. Though gracefully written and charming, it suggests that the family stream may be running thin.

Meanwhile, in Never Give In! (Hyperion, $ 27.95), Churchill's grandson Winston has selected and introduced what he considers to be the best of Churchill's speeches. The opportunity to sample Churchill's oratory conveniently, in a format unmediated by others, is a welcome addition.

John Ramsden, an academic historian whose field is British politics and the Conservative Party, tries to deal with Churchill's life and legend since 1945. He sets out in Man of the Century (Columbia Univ., $ 37.50) to elucidate how Churchill's "fame was created, perceived, marketed, spun and, in some cases, even fabricated." Ramsden is handicapped by unfamiliarity with Churchill's life and with world affairs and by an inability to employ consistent, discernible logic. While acknowledging Churchill's greatness, Ramsden often gives the impression of a pigeon astride a colossal statue.

Even when he gets a fact right the first time, he often gets it wrong the next. He recalls the remarkable statement made by Churchill in 1946, that there was one country in which he would now wish to be born, the one country that had an unbounded future, the United States. Later relying on the same statement, Ramsden presents it as Churchill saying that he wished he had been born in America. Ramsden fails to see the difference between saying, as Churchill did not, that in 1874, with British power at its apogee, he would have preferred America, and saying that in 1946, at the peak of American might, he would have preferred his birthplace to be America.

In 1956, Anthony Eden diagnosed Nasser as a new Hitler who had to be stopped at Suez. With astonishing ignorance, Ramsden claims that Eden based his position on what Ramsden considers Churchill's oversimplified published account of British appeasement in the 1930s. But during that period, Eden was foreign secretary and surely drew his 1956 appreciation of appeasement from his own experience.

At Churchill's memorial service in 1965, the congregation in St. Paul's Cathedral sang "The Battle Hymn of the Republic." American and British flags flew together along the length of the procession. Inside the west door of Westminster Abbey hangs a tablet "To the Honored Memory of Franklin Delano Roosevelt, a faithful friend of freedom and of Britain." Nearby, on the floor of the nave, is a marble slab stating simply, "Remember Winston Churchill." Churchill remains the only honorary citizen of the United States. The placement of his statue in Washington, with one foot on British soil within the embassy grounds and the other on American soil, is unique. A Martian who read Ramsden's book might not understand these honors. A reader of Meacham's book would think them insufficient.

Daniel Davidson, a Washington lawyer, regularly reviews books for the Economist.