Carlos Fuentes's highly lauded Terra Nostra is now available as a Farrar, Straus & Giroux paperback [$6.95], Schocken Books has a new paperback edition of Louisa May Alcott's novel, Work, with an introduction by Sarah Elbert [$5.95]. Two recent Dover paperbacks are Gaston Leroux's The Mystery of the Yellow Room[$3.00] and Anthony Trollope's The Claverings, with an introduction by Norman Donaldson [$5.00]. Emerson Price's Inn of That Journey has been added to Southern Illinois's Lost American Fiction series [$7.95, hardback]. Another addition to that series is Peter Martin's The Landsmen[$8.95, hardback]. Donald Windham's Tanaquil has been republished in hard-back by Holt, Rinehart and Winston [$8.95], Now out in the Norton Critical Edition series are George Eliot's Middlemarch, edited by Bert G. Hornback [$15.95], and Thomas Hardy's The Mayor of Casterbridge, edited by James K. Robinson [$12.95]. New Bantam Books include Les Whitten's Conflict of Interest [$1.95], T. Ernesto Bethancourt's The Dog Days of Arthur Cane [$1.50], and Leon Uris's world bestseller Trinity [$2.75]. Flannery O'Connor's A Good Man is Hard to Find is a Harvest paperback from Harcourt Brace Jovanovich [$3.45].