THE TIME OF MY LIFE <i> By Denis Healey (W.W</i> . <i> Norton: $29.95; 607 pp.) </i>

When this book was published in London last year, the Economist was compelled to call Denis Healey “probably the best prime minister Britain never had.” It’s hard to argue with that assessment, for Healey comes through in “The Time of My Life” as a man of conviction, confidence and significant political savvy. More important, he also demonstrates a clear political philosophy--call it “liberal pragmatism”--that ensured, paradoxically, both his leadership in the Labour Party and his failure to take up residence at 10 Downing Street. Healey often writes that he would much rather “do” than “be,” and that’s easy to believe; often described as a loner, Healey seems more interested in the job of governance than in promoting himself.

“The Time of My Life” often is less than engaging for that very reason--arms control and budgeting issues (Healey was defence secretary from 1964 to 1970, chancellor of the exchequer from 1974 to 1979) are sufficiently technical to be only intermittently interesting. However, Healey’s description of Labour politics is absorbing, largely because it parallels that of the Democratic party in this country; the ascendancy of the conservative viewpoint in both the United States and the United Kingdom is directly linked to decades of liberal backbiting and indecisiveness.

Healey distinguishes himself from most American political memoirists by failing to spend much time settling old scores--although when he does, he’s wickedly effective. Of Harold Wilson during his first term as prime minister, he writes: “ . . . a capacity for self-delusion which made Walter Mitty appear unimaginative.” Of a fellow Member of Parliament: “I cannot say my heart always rose when his long anteater’s proboscis began to quiver, and his mouth began its gobbling splutter.” Of Lyndon Johnson: simply “a monster.”

“The Time of My Life,” in short, contains gems, but they take some excavating to find.