“Fetch” is an old word for a double. It’s that secret self, often scarcely known to us, we dispatch on errands we’re too timid to undertake on our own. We stay home, listening to the rain beat against the windowpanes, but our fetch is on the prowl, stepping boldly into shady dives and shadier adventures. In her third collection of poems, the American poet Tamar Yoseloff, long a resident of London, uses the notion of the fetch to give structure and resonance to a sequence of strong but delicate lyrics. “Fetch” (Salt, 62pages, $14.95) strikes me as one of the best collections to have appeared in 2007. The book, with woodblock illustrations by the artist Linda Karshan, is elegantly designed too. (Though Salt is an English publisher, its books are distributed in America.)

Ms. Yoseloff divides her collection into five sections, each opening with a “Fetch” poem. These are spooky poems, mostly in quite spare free verse. In one, the fetch becomes an anonymous stalker:

I choose her uniform—
sunglasses, trenchcoat.
She needs to lose herself
in a crowd, to be invisible.

The lines are clipped, like a roman noir set out in verse. The fetch must discover not only “where he goes, who he meets,” but whether “he still wears that blue shirt.” The blue shirt seems only a brief dab of color, but in other poems, it flashes back, not only from “the indigo sea,” but in the cadmium of “Illumination,” where

The monks ground azurite and lapis
for perfect blue, took care
to cleanse their hands of poison
that made words sacred.

Whether Ms. Yoseloff writes about a seal on a beach (she’s especially good on seascapes) or a Venetian mirror with its “crystallized gloom” or the “glissando” of “black silk,” she inserts small touches of color that flash between the poems and link them. For all its restraint, this is a sensuous book; the yellow of the gorse has a scent “like sweat on skin.

When Ms. Yoseloff abandons restraint, the results are startling. In “The Visitants,” a herd of elephants thunders through London until “they enter Hackney in a fluster of tusks.” The elephants “bat their eyes,” but you hear “the ocean of sadness they carry.” They trumpet through Piccadilly and yet,

they never forget the land where they were born,
the bitter taste of heat and ashes on their tongues,
the sweet fruit, overripe to bursting,
so strong in them that they open their mouths and sing.

Her zaniest poem in this vein is “The Dentist.” She catches that queasy sense of intrusion we all feel in the dentist’s chair, both hygienic and prurient:

He runs his thumb slowly over the peaks
of lower molars, cupping my chin in his palm,
over that stubborn incisor that refused
to be straightened. He rubs the sharp canine…

As the poem progresses, the reader begins to wish Ms. Yoseloff had sent her fetch to the dentist. Never mind: This is a lovely book, full of sly surprises.