The poet Mary Oliver died on January 17. She won the National Book Award and the Pulitzer Prize for her poetry. But it was her prose that I found most marvelous. I discovered it a few years ago, and her book Upstream is beside me now — with such a flurry of Post-it tabs that it looks as if I’ve bookmarked every page.

Oliver writes of the natural world, of shaggy dunes and the blue-black of pond water; of fields and woods “and the possibility of the world salvaged from the lords of profit.” We should teach our children the names of hepatica and sassafras and wintergreen, she says. Why? Because “attention is the beginning of devotion.”

Oliver acknowledges her debts to those who came before, the “immeasurable fund of thoughts and ideas, from writers and thinkers long gone into the ground — and inseparably from those wisdoms because demanded by them, the responsibility to live thoughtfully and intelligently.”

Now Oliver is gone. And yet she is with me now more than ever. I read her often because she is a writer’s writer who whispers — no, shouts — do it, do it now, because if you don’t, you will always be sorry. “The most regretful people on earth,” she writes, “are those who felt the call to creative work, who felt their own creative power restive and uprising, and gave to it neither power nor time.”