Sun Yat Sen's biography is a task only Pearl Buck would have the temerity to attempt for younger readers. And even in the able hands of a writer who is also a student of the Orient, it is not wholly successful. Possibly because Sun's adventures were adventures of the mind and spirit- and it makes it difficult to capture and hold attention without drama. The chief value of the book, for those who will read it, is that it introduces to young Americans a China with a heritage of greatness and culture, at a point when progress was strangled, and one man's vision helped her people free themselves from bondage. The appeal is one that needs direction. Few -- even at twelve and thirteen -- would seek it for themselves.