The book I'm referring to and highly recommending is titled "By Trust Betrayed: Patients, Physicians, and the License to Kill in the Third Reich", by Hugh Gregory Gallagher.
To quote from the back cover:
"By Trust Betrayed" provides new insight into the horrors of
ordinary people doing monstrous things under the aegis of "science" in Nazi
Germany. It also raises troubling questions about many contemporary
theories and ideas dealing with euthanasia, health care, and medical