“What I’m most passionate about, much much more than all the rest in my profession,” said Vincent van Gogh, “is the portrait, the modern portrait.” While living a secluded life in Arles, Van Gogh painted portraits of a neighboring family he befriended, the Roulins. The father, Joseph Roulin, was a postman, and he and his wife had three children. Van Gogh and Joseph spoke often; the family’s happy nucleus perhaps represented a comfort that the artist had always yearned for but never achieved. In his paintings of the Roulins, the family members don’t appear particularly joyous, but the brushstrokes and backgrounds—often featuring them among myriad flowers—reveal tenderness. A large number of these paintings, along with letters, bring to life Van Gogh’s world in Arles, where he waited in vain for Paul Gauguin and companionship amid the sunflowers. —Elena Clavarino