PAC Power: Inside the World of Political Action Committees, by Larry J. Sabato (Norton, $4.95). The growing influence of political action committees in the US has given rise to alarm. Yet, to some extent, the burgeoning of PAC power is a result of campaign reform measures that limited the contributions of individual ``fat cats.'' Professor Sabato examines, in minute detail, many aspects of the phenomenon -- fund-raising, spending, lobbying, and general organization of PACs -- without becoming overhea ted or losing his sense of humor. His conclusion, roughly paraphrased, is that money always finds a way, and that PACs, though sometimes harmful, are at least an openly identifiable way for us to trace the relationships between money and politics. The Jews of Hope: The Plight of Soviet Jewry, by Martin Gilbert (Penguin, $6.95). The distinguished historian and official biographer of Winston Churchill, Martin Gilbert, provides a moving, even harrowing account of the plight of the ``refuseniks,'' Soviet Jews who refuse to give up their religious identity and who have been denied the right to leave the country that continues to persecute them. Mr. Gilbert, who traveled to the Soviet Union in 1983, describes his meetings with individual refuseniks and di scusses the general atmosphere of Soviet anti-Semitism, including propaganda that portrays Jews as allies of the Nazis. His book is filled with things that inspire anger, sympathy, sadness -- and admiration. To Jerusalem and Back: A Personal Account, by Saul Bellow (Penguin, $4.95). First published in 1976, Bellow's account of a visit to Israel is not only a keenly observant record of the country and people he saw, but also a series of skillful responses to various criticisms of Zionism and the Jewish state. Like his fiction, Bellow's nonfiction displays his powerful grasp of reality. Prisoner of Grace, Except the Lord, Not Honour More, by Joyce Cary (New Directions, $7.95 each). Joyce Cary's ``Second Trilogy'' is also a triangle. Each novel is told from the viewpoint of a different participant: Chester Nimmo, an impassioned, evangelical left-wing politician; Nina Woodville, the woman he marries; Jim Latter, a right-wing soldier who becomes Nina's second husband. Public and private lives clash, as do values, politics, and personalities. The action climaxes during Britain's general strik e of 1926. Quite a different triangle is the subject of William Dean Howells's charming romance, Indian Summer (Fromm, $8.95). First published in 1886, this romance features one youthful and two middle-aged participants and is set in Florence, Italy. Howells, whose place in literary history has often been overshadowed, is well worth a second look. The Birthday King, by Gabriel Fielding (Phoenix Fiction/University of Chicago Press, $8.95). The Phoenix Fiction series has reissued works by J. B. Priestley, R. K. Narayan, J. I. M. Stewart, Henry Green, Michael Campbell, and others. In this unusual novel, first published in 1962, Fielding takes us inside the world of a wealthy German family -- part Jewish, part Roman Catholic -- and reveals the contrasting lives of two brothers during the years of Hitler's reign. The novel's striking quality of verisimilitude is a triumph of artistic imagination. The Virago Modern Classics series, recently taken over by Penguin, revives writing by women. Among the recent titles are three by the British writer Elizabeth Taylor (1912-1975): The Wedding Group ($6.95), Palladian ($6.95), and a collection of short stories, The Devastating Boys ($6.95). Taylor's work has won her a devoted readership that includes many of her fellow craftsmen who admire her quiet mastery. Considering how well appreciated her fiction is, it is hard to imagine why her stories are pref aced by an ill-considered, needlessly contentious introduction by Paul Bailey. Virago is also reissuing a novel, Company Parade ($6.95), and short stories, Women Against Men ($6.95), by Storm Jameson, very capably introduced by poet and novelist Elaine Feinstin. Ms. Jameson, who is 94, wrote these books more than 50 years ago, but her writing has retained its strength and its passionate honesty. Ruth, by Elizabeth Gaskell, edited with an introduction by Alan Shelston (The World's Classics/Oxford University Press, $4.95). This compassionate novel about an unwed mother caused considerable consternation in its time (1853). Mrs. Gaskell, Victorian novelist and biographer of Charlotte Bront"e, is a fine writer, sensitive to social conditions and psychological nuances. William Allingham: A Diary, 1824-1889, (Penguin, $5.95) provides fascinating glimpses into the lives of more than a few great Victorians. The Irish-born Allingham, who was a popular though mediocre poet himself, possessed a wonderful talent for recording the conversation and behavior of his friends and associates, who included Carlyle, Tennyson, Rossetti, Browning, Darwin, George Eliot, George Henry Lewes, Thackeray, Ruskin, and William Morris. John Julius Norwich provides an inviting introduction. Louis Armstrong: An American Genius, by James Lincoln Collier (Oxford University Press, $9.95). This comprehensive, well-researched, highly readable biography deftly separates fact from myth in telling the rags-to-riches saga of Armstrong's life. At the same time, Mr. Collier succeeds in blending appreciation, perception, and just the right amount of critical distance in analyzing Armstrong's central role in changing the style and sound of American music.