Michelle Obama Signs Books Tuesday at Politics and Prose

Michelle Obama is signing copies of her gardening book, "American Grown: The Story of the White House Garden and Gardens Across America," at a bookstore in upper Northwest.

Scores of people, including men and women pushing babies in plastic-covered strollers, lined up in the rain Tuesday outside Politics and Prose in Chevy Chase, D.C. Those attending had to get wristbands ahead of time and underwent a security clearance.

Before she took a seat and started signing books, the first lady told patrons to "buy away" because Mother's Day is Sunday. She said her book, which tells the story of the White House garden, is a great gift.

"American Grown" was published last spring. It is Michelle Obama's first book. The publisher says more than 175,000 copies have been printed.

All proceeds from the book sales will go to the National Park Foundation.

Politics and Prose said it's "thrilled" to host the event.