Book Two, page 114

The two-way mirror in Dr. Bianchi's office, from both perspectives.

A two-way mirror is a glass panel which appears to be solidly reflective on one side, but is in reality only mirror-tinted, allowing an individual on the reverse side to see through the glass. Two-way mirrors are often seen in interrogation rooms to allow the identities of the viewers to go unnoticed, or are employed to covertly spy on people in public facilties. At the Social Welfare Agency, many such mirrors are installed in places ranging from the post-operative rooms where newly cyberized girls recuperate after surgery, to Dr. Bianchi's office. Only selected individuals are allowed to surveil the subjects on the other side, however, typically permitted handlers or Ferro.