Popular Library has published a paper-back edition of "The Children of Pride," edited by Robert Manson Myers, in a three-volume set [$9.75]. Individual volumes of the National Book Award winner about the joys and sorrows of a Southern family just before and during the Civil War are also available [$3.25], their titles being, respectively, "Many Mansions," "The Edge of the Sword" and "The Night Season." Schocken Books has reprinted "Life and Writings of Amelia Bloomer," she having been a pioneer in the women's rights movement, with a new introduction by Susan J. Kleinberg [$3.95]. Vintage Books has brought out a mammoth one-volume edition of Robert A. Caro's comprehensive and controversial account of the empire that Robert Moses, "The Power Broker," built in and around the empire city of New York [$7.95]. "One Man's Road to Watergate," the man being former Nixon aide Jeb Stuart Magruder, is a new Pocket Books selection [$1.95]. Penguin Books has "Justices and Presidents," Henry J. Abraham's political history of appointments to the Supreme Court, among its current offerings [$2.95]. A new Delta reprint is Vine Deloria, Jr. 's "God Is Red," a work offering an alternative to Christianity through a return to Indian beliefs and concepts [$2.95].