Johannes Vermeer is probably best known for “Girl with a Pearl Earring,” his intimate portrait of a young woman who sort of looked like Scarlett Johansson. The mystery behind that subject’s eyes has aroused curiosity in countless viewers, but enigma is central to many of this Vermeer’s works. In “Woman in Blue Reading a Letter,” another young woman is so caught up in the contents of her correspondence that she seems oblivious to everything around her. It leaves the viewer craning to see what’s written on the page in her hand. You can guess for yourself at the National Gallery, where the painting, on loan from Amsterdam’s Rijksmuseum, is on view for the first time in 20 years. Even if you’ve seen it before, it’s worth another visit to see the restored work, one of only 34 paintings credited to the artist. Vermeer and his fellow Dutch masters, like Rembrandt, were known for their luminous paint—now, this mysterious woman’s blue dress shimmers like it must have 350 years ago. The exhibition is on view Mondays through Saturdays 10 a.m. to 5 p.m. and Sundays 11 a.m. to 6 p.m. at the National Gallery of Art, 6th Street and Constitution Avenue NW. Free. (202) 737-4215. nga.gov.