George Tiller had been providing abortion services since the early 1970s
To some anti-abortionists George Tiller, who was shot dead on Sunday, was a mass murderer known as "Tiller the Killer". To his patients and many pro-choice supporters, he was a hero committed to women in need of help.
For two decades, Dr Tiller spent his life looking over his shoulder. He had become a lightning rod for anti-abortion activists and in 1993 survived an attempt on his life.
He rarely talked about his work for fear of attacks against himself or his family.
Dr Tiller's clinic was one of three in the US that offered what are known as late-term abortions.
WHAT IS LATE TERM?
Late term mostly centres on the notion of the "viability" of the foetus - this is widely interpreted as when the foetus has the capacity for sustained survival outside the womb
The Supreme Court recognises viability varies from pregnancy to pregnancy and that determination of viability is a matter for the judgement of the attending physician
Under Kansas law, aborting a viable foetus is legal only if two doctors certify that continuing the pregnancy could kill the woman or cause "substantial and irreversible impairment of a major bodily function".
The Supreme Court has made it clear a woman's mental health may be taken into consideration
He had acknowledged that abortion was as socially divisive as slavery, but said the issue was about giving women a choice when dealing with technology that could diagnose severe foetal abnormalities.
For decades, his clinic in Wichita, Kansas was besieged by protesters, some carrying signs, others carrying Bibles.
Speaking in court earlier this year after being charged with performing 19 illegal abortions, he told a jury why he continued his work despite the opposition.
"Quit is not something I like to do," he said. He said he firmly believed his patients needed him and that he had the "strong support of his family".
Dr Tiller outlined a conversation he had had with his daughters - two of whom are physicians - in which he said the importance of his work was crystallised.
Dr Tiller survived an attempt on his life iin 1993
"My daughters came into my study," he said. "I was reading. And they said, 'Daddy, if not now, when? If not you, who? Who is going to stand up for women with unexpected and badly damaged babies?' I had the support of my family, and we were able to proceed ahead."
Kansas restricts abortions after 22 weeks of pregnancy, except where the mother's health would be seriously harmed if the pregnancy continued.
Doctors are required to consult an independent physician before performing an abortion after the 22nd week of pregnancy.
The case raised questions about whether Dr Tiller had been too closely linked to a doctor from whom he sought second opinions.
He was acquitted in the case.
According to reports, Dr Tiller had talked of carrying out hundreds of late-term abortions since the second-opinion law took effect in 1998.
He faced a number of other legal challenges, including two separate grand jury investigations which were convened as a result of what are known as citizen-led petitions. Both ended without charges.
Dr Tiller was shot in the lobby of the church, reports say
According to his website - which was removed after his death - Dr Tiller graduated from the University of Kansas School of Medicine in 1967.
He served his internship at the US Naval Hospital at Camp Pendleton, California, and worked as a flight surgeon for the Navy until 1970.
He began practising in Wichita that year, specialising in family medicine. He inherited his father's practice after his parents were killed in an accident.
Anti-abortion activists claimed Dr Tiller was performing late-term abortions for relatively minor foetal abnormalities.
He has acknowledged performing abortions on some late-term patients with healthy foetuses.
Reportedly among them were girls as young as 10, rape victims, alcoholics, drug addicts, and women who were suicidal or depressed. Some anti-abortionists, however, questioned his criteria for diagnosing depression.
In the early 1990s, Dr Tiller bought a second clinic in Wichita and tried to acquire a third. This, along with the reduction of fees for a first-trimester abortion, further antagonised abortion foes.
It even caused dismay among some abortion-rights supporters, who criticised him for seeking to create a monopoly.
In 1991, anti-abortion activists launched a massive protest - known as Operation Rescue - against his clinic. It lasted more than six weeks and resulted in about 2,800 arrests.
In 1993, Dr Tiller was shot in both arms outside his clinic. The incident came five months after the shooting of another abortion doctor.
His clinic was subsequently heavily fortified and Dr Tiller was often forced to travel with a bodyguard.
Recently, President Barack Obama's choice for health secretary, former Kansas governor Kathleen Sebelius, was widely condemned by the anti-abortion movement because she had received campaign money from Dr Tiller.