In 2013, the art historian Lindsay Stainton looked through a bound album of 18th-century sketches, their subject the British countryside, and noticed something peculiar. Although the sketches had long been attributed to Sir Edwin Landseer—and had been acquired by Queen Victoria from his studio in 1874—Stainton recognized one as a preliminary sketch for Thomas Gainsborough’s celebrated 1748 landscape Cornard Wood. Stainton had uncovered a mystery the art world didn’t know existed, and simultaneously solved it. The 25 sketches weren’t drawn by Landseer but by Gainsborough, an artist beloved for his idyllic portraits and landscapes, but not previously known for his draftsmanship. These misattributed nature sketches are now on display for the first time. The drawings—which render Gainsborough’s native Suffolk as well as imagined landscapes—offer insight into the artist’s early work. —J.D.