The so called „T4 operation“, so titled for the street address of the office in charge, was the centrally organized „euthanasia“ of national socialist which brought death to more than 70.000 people. This operation was the first systematically planned and realised extermination against a week minority within the „Third Reich“. Mainly inmates and patients of asylums were murdered at six, especially for the purpose equipped hospital grounds, the so-called extermination sites. The people were killed by gas in newly constructed gas chambers. The T4 operation must be seen as a central part of the patient killing during the Nazi period which counted more than 300.000 victims and which was connected with the holocaust due to the fact that the physicians and nurses involved in the patient murder were taken as experts to concentration camps in Eastern Europe for their advise.
This publication presents the current state of research on the organisation of the T4 operation as well as the first results of a large-scale study focussing on the victims and their biographies.
h-madness 
Thanks for this chilling post. Readers might be interested to know about a recent paper on the same topic, which has rather detailed estimates on the sterilization and euthanasia of asylum patients:
Torrey EF and Yolken RH (2010) Psychiatric genocide: Nazi attempts to eradicate schizophrenia. Schizophrenia Bulletin 36: 26–32.
A chilling & much needed continued conversation.
Will this be translated or are there translations already available? Also, could someone recommend additional books/texts on this topic?
Jessica
Thank you very much for your interest! A translation of the book is not available, one of the papers is in english (on T4 in Slovenia). The International Journal of Mental Health 35 (2006) publishes an issue on national socialist patient murder. One of the papers there collected was written by our research group (The First National Socialist Extermination Crime: the so-called “T4 Program” and its Victims, S. 17-29. But there ara a loot of other texts on this topic …