For Prof. Emerson (English, Chapel Hill), the ""authentic Mark Twain"" pops up only rarely through the large output of Sam Clemens--which is chronologically surveyed, with brief critiques, in this dry, somewhat simplistic, yet useful study. Emerson follows young Clemens from childhood through early newspaper jobs--appraising the fledgling writings (many of them now unfamiliar), reporting on literary influences, not really venturing into the personal side of biography. (""The origins of Samuel Clemens' interest in humor and in writing appear to be his pleasure from books."") He charts the emergence of the authentic Twain: skeptical, irreverent, anti-genteel, celebrating vernacular values. But, even at the start, with The Innocents Abroad, Emerson finds Clemens compromising to appease ""Middle Americans""--the dominant theme thereafter. In Tom Sawyer, he ""was able to combine his desire to write a popular. . . book and his belief that small-town America had little to offer a person who would live both freely and intensely."" The less-well-known ""Carnival of Crime"" is an irreverent ""masterpiece."" And Huckleberry Finn achieved greatness by confronting and dramatizing the Clemens/Twain conflict. Otherwise, however, influenced by genteel wife Olivia and money-making ambitions, Clemens would ""resist, almost betray his genius""--in Life on the Mississippi (Mark Twain ""disappears"" from the last 38 chapters), in A Connecticut Yankee (""he raised issues beyond his grasp""), in his increasing role as a would-be social philosopher of pessimistic determinism. (Only occasionally--in ""The Chronicle of Young Satan"" and the posthumous ""Letters from the Earth""--did the free spirit resurface.) Emerson tends to overstate his thesis throughout this study, which is thin on biographical detail or interpretation; the influence of Twain's reading is also exaggerated, sometimes even given more importance than psychology. But the analysis of many unfamiliar (or unpublished) Twain works is welcome. And students who are careful to take this ""literary biography"" only on its own limited terms will find it firmly valuable.