While the mistress concentrates on writing, the maid looks out of the window. Another Vermeer shows the mistress and maid theme: The Love Letter, but in this the interaction between the women is the subject, whereas here the women look in opposite directions.
The composition moves the eye towards the women from both sides. from the right we see a chair and a rich oriental rug covering the table; the chair invites us in, while the table is a barrier. From the left the sequence is a dark curtain, the window, and an exquisitely rendered translucent curtain that seems to be painted from light itself. The mistress is dressed in a starched blouse, rendered with sharp polygons of white, and pearl jewelry. On the floor in front of the table is a seal and sealing wax for completing the letter, and also a crumpled sheet, which may be an initial version of the letter she is writing, or it may be the letter to which she is responding.
The large painting on the wall behind the women is The Finding of Moses, the same painting as in The Astronomer, but not the same size. This indicates that somebody must be rescued and cherished, but it is not clear who that is.