Over the years Father Moffatt has become an author-spiritual-director to a wide audience of Nuns for whom he writes his ""Sister"" series of books including Look, Sister; Pray, Sister; and last year's Step This Way, Sister. The format and material of Think, Sister differs little from its predecessors, although the author suggests that his readers can adapt its subject matter to their moments of prayerful thinking. Father Moffatt contends that the daily consecration to God which ushers in every Nun's day makes it holy, and enables her to accept the ""Death to Self"" entailed in performing her every duty from the motive of pure love. While the ideas in Think, Sister deserve commendation present-day, well-educated Nuns may find Father Moffatt's tendency to give Sisters names like Sister Mary Arodosa or Sister Mary Impetuosa does get cloying. And they may feel that his writing is on the saccharine side and divorced from reality. Most Nuns are well aware of what's going on in the world without being told, ""out there in the world the fiend of hell is stalking an innocent victim whispering into its ear his vile suggestions, urging its faltering steps along the alluring path that leads to ruin, cajoling it with specious sophistries till its defenses are gradually weakening and even is well-nigh ready to yield and accept the deadly poison mingled with the cup of forbidden pleasure he offers."" They deserve more credible writing than that in a book which proposes to help them dwell on the ""great eternal realities, on life's serious purpose and on the unending existence to which this life is a fleeting prelude.