[The essay from which this excerpt is taken originally appeared in 1979 as an introduction to Peter Matthiessen, A Bibliography: 1951–1979, compiled by D. Nichols.]

I read Partisans and Raditzer with the same careful eye that I had Race Rock; as talented and sensitive as each appeared to be, the statement of a writer at the outset of his career, they were, I felt, merely forerunners of something more ambitious, more complex and substantial—and I was right. When At Play in the Fields of the Lord was published in 1965 there was revealed in stunning outline the fully realized work of a novelist writing at white heat and at the peak of his powers; a dense, rich, musical book, filled with tragic and comic resonances, it is fiction of genuine stature, with a staying power that makes it as remarkable to read now as when it first appeared.

But before At Play was published Peter had to begin that wandering yet consecrated phase of his career which has taken him to every corner of the globe, and which, reflected in a remarkable series of chronicles, has placed him at the forefront of the naturalists of his time. (p. 251)

From what sprang this amazing obsession to plant one's feet upon the most exotic quarters of the earth, to traverse festering swamps and to scale the aching heights of implausible mountains? The wanderlust and feeling for adventure that is in many men, I suppose, but mercifully Peter has been more than a mere adventurer: he is a poet and a scientist, and the mingling of these two personae has given us such carefully observed, unsentimental, yet lyrically echoing works as The Cloud Forest, Under the Mountain Wall, The Tree Where Man Was Born and The Snow Leopard. In the books themselves the reader will find at least part of the answer to the reason for Peter's quest. In these books, with their infusion of the ecological and the anthropological, with their unshrinking vision of man in mysterious and uneasy interplay with nature—books at once descriptive and analytical, scrupulous and vivid in detail, sometimes amusing, often meditative and mystical—Peter Matthiessen has created a unique body of work. It is the work of a man in ecstatic contemplation of our beautiful and inexplicable planet. To this body of natural history, add a novel like At Play in the Fields of the Lord and that brooding, briny, stormswept tone poem, Far Tortuga, and we behold a writer of phenomenal scope and versatility. (pp. 251-52)