This painting is a mystery. We do not know what this woman looks like, and we are concerned about her body shape. She appears to be pregnant. We also do not know what letter she is reading. The light coming from the left is said to be the morning sun. On the wall behind the woman is a map. The theme of this painting is blue. Blue is used to weight the woman's clothes, the chair, the light on the wall, and the map hanging on the wall. In this work, Vermeer uses quite distinctive expressions, such as the woman's skin in a light gray color and the blue light on the wall.