C. S. Lewis died only 16 years ago, yet already his readers have begun the single-minded process of literary canonization. Sales of his books have never been better - "going through the roof," exclaims an American publisher. A film of his life has been made; the first of his Narnia tales has appeared on television, and movie rights to several books have been sold. C. S. Lewis societies and study groups fleck the globe; apocryphal stories concerning him are legion. One college claims to possess the magic wardrobe through which the children entered Narnia - a first-class relic.

In spite of all this hoopla, however, Lewis is luckier than most cult figures. Earlier this year he was the principal figure in Humphrey Carpenter's superlative book, The Inklings, and he is now the subject of two thoughtful, well-wrought studies that should serve to clarify rather than to mythologize the man and his canon: The Literary Legacy of C. S. Lewis, by Chad Walsh, and C. S. Lewis at the Breakfast Table, edited by James T. Como. Though their natures differ - Walsh's is a critical study and Como's a collection of personal reminiscences - both books are suffused with admiration for Lewis, but this admiration is laced with good sense and sound judgment.

The difficulties inherent in evaluating Lewis' corpus are formidable. He wrote over 50 books, most of which - even his science fiction - recall classical literary forms: medieval dream visions, allegories, bestiaries, allegorical fairy tales, fantasies, and 19th-century apologetical tracts.

His ars poetica was decidedly not modern. Originality Lewis deemed the last refuge of literary scoundrels; instead, he chose to retell and, by the retelling, to enrich older stories culled from biblical and mythological sources. Mankind, Lewis averred, has yarns enough to satisfy the imagination of any writer. A staunch moralist - one more trait he shared with writers of other eras - he wrote to delight, instruct and edify. The roles of teacher and legislator of morals Lewis vigorously, joyfully acknowledged. Clearly his literary sensibilities were out of joint with his times.

Writing about such an author - to employ Lewis's self-characterization - is akin to studying a dinosaur. The critic had best possess the literary, theological, philosophical, and rhetorical tools to dissect, reassemble and properly mount his speciment from the past.

For such a task, Chad Walsh is well suited. His earlier study of Lewis, C. S. Lewis: Apostle to the Skeptics, published in 1949, was the first critical book wholly devoted to Lewis. His present work is the first to examine all of Lewis's major works, from the "middle distance of a half-generation after his death." Doggedly, Walsh scrutinizes Lewis' major and many of his minor works. He judges that Lewis' poetry lacks subtlety and range; in general, it is uninspired and thin. Only when Lewis manages to wed his unrelenting logical mind to his visual imagination does he produce anything distinctive, anything liable to last: the space trilogy, the Narnia stories, Pilgrim's Regress, The Screwtape Letters. In these books, Walsh writes, Lewis, a lesser Dante or Milton, fashions a secondary world in which supernatural dramas are enacted. Indeed, Walsh continues, Lewis, adapter and maker of myths, has given the the world books that "take their places as a subdivision of the great mythologies that have supplied meaning to so many civilizations."

Lewis's important scholarly books - The Allegory of Love and The Oxford History of English Literature: English Literature in the Sixteenth Century, Excluding Drama - are, unlike most books of literary history, composed with solid erudition as well as crackling wit. They whet the reader's appetite to return to the originals. They will be read, Walsh predicts, if not for their contributions to scholarship, then for their pellucid and entertaining style.

Walsh pays special attention to Till We Have Faces, Lewis's last work of fiction. He sees it as a glorious failure - a late work that is uncharacteristically marked not by clarity, but by ambiguity and Dostoevskean depth. It is Lewis's dark, demonic tower on an otherwise sunlit plain.

But the task Walsh has undertaken is almost too vast, even for such a learned critic. There are just too many works to be analyzed, and Walsh frequently lapses into summary and brisk comment. Generalizations abound; woefully absent are detailed analyses of Lewis' theoretical techniques. At times Walsh's reach exceeds his grasp - as often happened to Lewis. But, given even these lacks, Walsh's book is a major attempt to assess the literary value of an "unusual and significant writer." At the very least, his well-written, solid treatise should encourage the reader to return to Lewis and to see for himself the extent of Lewis' achievement.

James T. Como's C. S. Lewis at the Breakfast Table is an unexpected delight. The contributors are either friends of Lewis - classmates, students, colleagues - or admirers who became acquainted with Lewis through reading his books. They are all so many Boswells producing, as memory serves them, a community biography that is packed with anecdote and insight. Without exception, the essays are witty and engrossing, a series of snapshots of Lewis from various angles: Lewis as friend, tutor, co-worker, hammer of heretics, spinner of worlds. The contributors may differ in their tones or emphasis, but all share one characteristic: they have been touched profoundly by their encounter with Lewis. He is remembered as the "best-read man of his generation, one who read everything and remembered everything he read"; the good man sho spoke well; the good man "to whom goodness did not come easily"; a Christian Humanist; Oxford's bonny fighter. Read separately, or in conjuction with Walsh's book, Como's volume helps to flesh out a man whom many of us have not been fortunate enough to meet.

Certainly more books on Lewis are in the offing. The Modern Language Association cites Lewis "as one of the most rapidly increasing objects of literary study in the world." Whether he has staying power, as Walsh argues, remains to be seen. Perhaps here Lewis should have the last word - as he usually did in life. What Lewis wrote of Spenser, Como points out, can also be applied to Lewis's own books: "His work is one, like a growing thing, a tree...with branches reaching to heaven and roots to hell...And between these two extremes comes all the multiplicity of human life." CAPTION: Picture, G. S. Lewis by John S. Murray