In 1897, on his way to India after making his first political speech, young Winston Churchill sent his mother this urgent request: “I want Lord Beaconsfield’s and Mr. Gladstone’s speeches!”

Churchill, in the words of historian Richard Aldous, recognized that modern British politics began with the clash between these two great antagonists, and that “the legend of both men was somehow embedded in the synergy of their rivalry.” This synergy is the subject of The Lion and the Unicorn (W.W. Norton & Co., $27.95), Professor Aldous’ illuminating and fast-paced account of the thirty-year duel between Gladstone and Disraeli.

The title derives from the popular belief that both politicians were satirized as mythical beasts in Lewis Carroll’s second book about Alice’s adventures in Wonderland. Punch, the humor magazine, was more explicit. In 1868, the editors ran a cartoon of the flamboyant Disraeli, in Elizabethan doublet and hose, preening himself before a mirror, while Gladstone, dressed as a proper Victorian gentleman, looks on with a scowl of disapproval on his face.

Like all good political cartoons, this one neatly summed up public perceptions of the two men depicted. Amid the staid ruling circles of Queen Victoria’s Britain, Disraeli was as rare and exotic a creature as one of the peacocks that strutted the terrace of his country house in Buckinghamshire. It was incredible that a Jew, a dandy and society novelist should be admitted to Parliament –- let alone become leader of the Conservative Party, prime minister and, ultimately, Lord Beaconsfield. But it happened.

Gladstone’s transformation was nearly as remarkable. A child of privilege, he attended Oxford and entered politics as a High Tory: a pillar of the established church and social order, and a knee-jerk opponent of any reform –- even the abolition of slavery. Yet in time he would become “The People’s William” –- the leader of liberals and radicals in Parliament, the opponent of British imperialism abroad and the champion of the common man at home.

Perhaps it was because both men were to some extent political chameleons that they so bitterly detested each other. Suspicion and hatred ran deep on both sides. Each was firmly convinced that the other was a mountebank and a menace, animated only by vanity and a thirst for power. And each said as much in public.

In 1877, for example, Russia threatened to overwhelm the Turkish Empire and menace the Suez Canal, Britain’s lifeline to India. Disraeli served notice that Britain would fight rather than cede Constantinople to the Russians. In reply, Gladstone launched an offensive of his own, denouncing Disraeli’s policy as “an act of war, a breach of European law.” He made his opposition personal, declaring openly that he had played “the part of an agitator. My purpose has been … to the best of my power, for the last eighteen months, day and night, week by week, month by month, to counterwork as well as I could, what I believe to be the purpose of Lord Beaconsfield.”

Unfortunately for Gladstone, not only did Disraeli manage to resolve the crisis by diplomacy instead of war, he added the island of Cyprus to the British Empire in the bargain. When Gladstone mocked Disraeli’s triumph as an “insane covenant”, Dizzy let him have it with both barrels. “Which do you believe most likely to enter an insane convention,” he asked in a speech following Gladstone’s outburst, “a body of English gentlemen honored by the favor of their sovereign and the confidence of their fellow-subjects, managing your affairs for five years, I hope with prudence, and not altogether without success, or a sophistical rhetorician, inebriated with the exuberance of his own verbosity, and gifted with an egotistical imagination that can at all times command interminable and inconsistent series of arguments to malign his opponent and glorify himself?”

Rhetorically speaking, Gladstone was at his best as a preacher, making high-flown moral pronouncements at outdoor political rallies. His speech in Edinburgh in 1879, attacking Disraeli’s imperialist policies, is one example:

“Remember that the sanctity of life in the hill villages of Afghanistan is as inviolable in the eyes of Almighty God as can be your own. Remember that He who has united you as human beings in the same flesh and blood has bound you by the laws of mutual love; that that mutual love is not limited by the shores of this island, is not limited by the boundaries of Christian civilization, that it passes over the whole surface of the earth and embraces the meanest along with the greatest in its unmeasured scope.”

(When Gladstone served as her prime minister, Queen Victoria made the famous complaint, “He speaks to me as if I were a public meeting.”)

Disraeli, a master of epigram, rarely made a speech without coining a phrase, such as, “Justice is truth in action,” or, “The English nation is never so great as in adversity.”

He also excelled in the cut and thrust of parliamentary debates. Once, he explained the difference between a misfortune and a calamity by this illustration: “If Gladstone fell into the Thames, it would be a misfortune. But if someone pulled him out, it would be a calamity!”

The Lion and the Unicorn. Small wonder that Winston Churchill studied both of them.