In 15 short prose pieces Pulitzer prizewinning poet Oliver entertains her ``sustaining passions'': love for the natural world and for literature. Only her musings on the latter subject sustains much passion in the reader. Oliver is an inveterate wanderer and noticer, and her observations of the ``wild world'' near her Provincetown home burst with the lush detail of an obsessive notebook-keeper. Whether she's stalking the woods in search of screech owls, cataloging the spoils of a day's beachcombing, or pondering the biodiversity of local ponds, the details add up to little more than pretty writing. The same can be said of notebook excerpts featuring odd lines of poetry, quotes from her reading, and snippets of observation; a cloying preciousness mars these overly long selections, which offer little insight into the poet's intellect but seem, instead, inaccessibly private. This sense contradicts Oliver's requirements for poetry: that it be about the reader, not the writer. Her essays on literaturewhich range from meditations on the creative life and the writing process to considerations of her favorite writers, Wordsworth, Keats, Poe, and especially Whitmanare more successful. Oliver stakes her aesthetic claim early and unequivocally in the book's opening essay, contending that ``the extraordinary is what art is about.'' She bemoans the loss of otherworldliness in modern confessional poetry, which profits from relaxed diction and personal, everyday subject matter (which, she perceptively notes, opened poetry to women and other previously underrepresented groups) at the expense of what she calls the metaphysics of the poem, ``the magical, the heroic, the imaginary existence.'' She questions the polarization separating metered poetry and free verse. Her sound advice to poets is synthesis: Learn the rules of meter before breaking them. Oliver devotees may enjoy the poet's delineation of her creative process. Newcomers would be better served by reading her poetry instead.