WINTER HOURS By Mary Oliver Houghton-Mifflin $22, 144 pp.

With poems of unparalleled clarity and insight, Mary Oliver captures the startlingly simple elegance of the natural world. In House of Light and other volumes of verse, she harnesses transient impressions of the outdoors and then questions our relationship with nature and with ourselves. Recognizing the tension between human morality and the amorality of nature itself, Oliver suggests that her readers reconsider their perceptions of the defining differences between humans and birds and blades of grass and even the inanimate objects that fill our world. But even as she has, in over 35 years of writing, explored questions of personal peace, Oliver has always avoided an autobiographical or otherwise intimate voice. In her new book, Winter Hours, however, Oliver brings us a collection of personal reflections, still carefully contemplative but in a voice clearly her own.

Winter Hours is an eclectic collection, including interpretations of Poe, Frost, Whitman and Oliver herself, along with several carefully crafted essays that reflect the Oliver's interest in personal growth through nature and use her personal experiences as a frame of reference. The book hops, often with little warning, from topic to topic and from literary form to literary form. But while its busy structure may be somewhat disconcerting, the clarity of each of Oliver's pieces and the meaning of her argument make up for its abrupt transitions.

Oliver's personal relationship with nature is both difficult to accept and difficult to condemn. For a poet grounded so firmly in the messages of nature, Oliver is often less of an environmentalist than one might expect. As she herself states, her impressions stem more from the experience of a "luminous life" than from an external environmentalist ethic. But regardless of whether Oliver's reasons for writing poetry are universal, her reasons are well-considered and interesting. Additionally, in speculating on the difference between her motivations, her intentions and her poetry, the veteran Oliver reader may be encouraged to formulate new, more thorough opinions of her work.

Winter Hours stands alone as a thought-provoking collection of opinions on writing about the natural world, a hodgepodge of different forms and topics, tied loosely together as the thoughts of Mary Oliver, poet. To a reader unfamiliar with Oliver's work, Winter Hours could seem insufficiently structured, its components only loosely related and its subject matter too concerned with Oliver's personal writing experience. But to one familiar with Oliver's poems, the book is a valuable window into the author's character and motivation. And regardless of the coherence of the book as a whole, each of the pieces in Winter Hours, considered separately, is thought-provoking and beautiful.