Jonathan Moreno, PhD, in the introduction to the 1995 book Arguing Euthanasia, explained:

“Passive euthanasia in the absence of knowledge of the patient’s wishes (nonvoluntary) remains controversial… Within the meaning of active euthanasia, the difference between voluntary euthanasia and nonvoluntary euthanasia is also important… active nonvoluntary euthanasia may be performed on a patient who is not competent and who has not requested it.”