In 2013, Associate Professor Teo You Yenn, head of sociology at Nanyang Technological University, began a study to better understand the lives of people who live in Housing Board rental flats.
Over three years, she spoke to more than 200 people in their homes about their experiences.
In January this year, she published a book of essays drawn from her ethnographic research.
This Is What Inequality Looks Like has received a warm reception, being one of the best-selling local books this year, with 20,000 copies sold so far.
It has helped propel inequality to the forefront of political discussions. Prime Minister Lee Hsien Loong has warned that the country will wither if it allows widening income inequalities to create a rigid and stratified social system. Education Minister Ong Ye Kung has said that tackling inequality is a national priority.
Many quoted from the book during discussions in Parliament, including former Nominated MPs Kuik Shiao-Yin and Kok Heng Leun.
Prof Teo, 43, thought at first that she would write a book on poverty.
"By going into people's homes, I saw how cramped their living spaces were. I saw how hard they had to work at their jobs, and I saw how their children were struggling in school," she said.
"Over the three years, I realised that I could not think of these experiences as disconnected from mine," she added.
"I saw similarities and contrasts. We all have the same hopes and dreams to work hard and care for our families. But we have different opportunities and face very different outcomes."
In the book, Prof Teo shows how class inequalities are embedded in education, labour, care and welfare.
"Within our system, some people have more options and more space to make decisions than others. This is what inequality looks like," she said.
Prof Teo said a key finding was that family life was bound up with other aspects, such as employment. Another finding was that children are central to parents' lives, and formal education is a key source of anxiety.
"When I was a child, my parents experienced a great deal of upward mobility. I was old enough to see that with a certain amount of money comes an array of different choices and opportunities," she said.
"If you have had opportunities in your life, then you have a responsibility to make sure that these opportunities are also available to others."
Now exploring how ordinary people think about basic needs, she said: "Inequality is a problem we own together - any change must come from many of us, in different fields and across generations."