Euthanasia (from the Greek: εὐθανασία meaning "good death": εὖ, eu (well or good) + θάνατος, thanatos (death)) refers to the practice of intentionally ending a life in order to relieve pain and suffering.

There are different euthanasia laws in each country. The British House of Lords Select Committee on Medical Ethics defines euthanasia as "a deliberate intervention undertaken with the express intention of ending a life, to relieve intractable suffering". In the Netherlands, euthanasia is understood as "termination of life by a doctor at the request of a patient".

Euthanasia is categorized in different ways, which include voluntary, non-voluntary, or involuntary. Voluntary euthanasia is legal in some countries and U.S. states. Non-voluntary euthanasia is illegal in all countries. However, in the Netherlands, physicians can avoid prosecution by following well described and strict conditions when non-voluntary euthanasia is performed on infants.Involuntary euthanasia is usually considered murder.

The Four Corners is a region of the United States consisting of the southwestern corner of Colorado, northwestern corner of New Mexico, northeastern corner of Arizona and southeastern corner of Utah. The Four Corners area is named after the quadripoint where the boundaries of the four states meet, where the Four Corners Monument is located. The majority of the Four Corners region is part of semi-autonomous indigenous American Indian nations, the largest of which is the Navajo Nation, followed by Hopi, Ute and Zuni Indian nations. The Four Corners region is part of a larger region known as the Colorado Plateau and is mostly rural, rugged and arid. In addition to the monument, commonly visited areas within Four Corners include Monument Valley, Mesa Verde National Park and Canyon de Chelly National Monument. The most populous city in the Four Corners region is Farmington, New Mexico, followed by Durango, Colorado.

The United States first acquired the area now called Four Corners from Mexico after the Mexican–American War in 1848. In 1863 Congress created Arizona Territory from the western part of New Mexico Territory. The boundary was defined as a line running due south from the southwest corner of Colorado Territory, which had been created in 1861. This was an unusual act of Congress, which almost always defined the boundaries of new territories as lines of latitude or longitude, or following rivers. By defining one boundary as starting at the corner of another Congress ensured the eventual creation of four states meeting at a point, regardless of the inevitable errors of boundary surveying. The area was first surveyed by the U.S. Government in 1868 as part of an effort to make Colorado Territory into a state, the first of the Four Corners states formed. The first marker was placed at the spot in 1912. The first Navajo tribal government was established in 1923 to regulate an increasing number of oil exploration activities on Navajo tribal lands.

Peter Albert David Singer (born 6 July 1946) is an Australian philosopher who is the Ira W. DeCamp Professor of Bioethics at Princeton University and Laureate Professor at the Centre for Applied Philosophy and Public Ethics at the University of Melbourne. He specialises in applied ethics and approaches ethical issues from a secular, preference utilitarian perspective.

He has served, on two occasions, as chair of philosophy at Monash University, where he founded its Centre for Human Bioethics. In 1996, he unsuccessfully stood as a Greens candidate for the Australian Senate. In 2004, he was recognised as the Australian Humanist of the Year by the Council of Australian Humanist Societies. He has been voted one of Australia's ten most influential public intellectuals. Singer serves on the Advisory Board of Incentives for Global Health, the NGO formed to develop the Health Impact Fund proposal.

Outside academic circles, Singer is best known for his book Animal Liberation, widely regarded as the touchstone of the animal liberation movement. Not all members of the animal liberation movement share this view, and Singer himself has said the media overstates his status. His views on that and other issues in bioethics have attracted attention and a degree of controversy.