Modern Slavery: A Global Perspective, is Kara's third book and culminating work on modern slavery. The book was launched at the United Nations in October 2017. The book provides a global overview of the key manifestations of slavery around the world, drawn from over sixteen years of research in over fifty countries. Using a case study format, the book explores sex trafficking and juju rituals in Nigeria, labor trafficking of agricultural workers to the Central Valley of California, debt bondage in the global construction and domestic worker sectors, organ trafficking in South Asia and across the Mexico-Texas border, slavery in global supply chains (seafood in Thailand), and the relationship between technology and human trafficking. The book is couched in the poignant narratives of numerous slaves Kara documented across the globe.

The book has been called "insightful and awe-inspiring" by the United Nations Special Rapporteur on Contemporary Forms of Slavery. Ambassador Swanee Hunt declares that "no reader, however carefully clad in hyper-rationality will emerge unchalleneged and unchanged;" and CEO of the Global Fund to End Modern Slavery Jean Baderscheider offers, "While many in this fight are sympathetic to the suffering [of slaves], Kara not oly brings to expertise, he brings true empathy."

Kara's third book also presents his groundbreaking metrics and economic analysis of modern slavery, demonstrating that slavery today is more profitable by far than at any point in human history. Kara identifies twenty forces that promote slavery in the world today, and he outlines a specific plan to eradite slavery, based on ten initiatives designed to dismantle the high-profit, low-risk business of modern slavery.

Kara's first book on slavery, Sex Trafficking: Inside the Business of Modern Slavery, was published in January 2009. The book won the 2010 Frederick Douglass Book Prize, a highly prestigious award that is given to the most outstanding nonfiction book on the subject of slavery. Since the inception of the Award in 1999, numerous books on the subject of modern-day slavery have been submitted, but Kara's book was the first to be awarded the prize.

The book has been recommended by the Under-Secretary-General of the United Nations and head of the United Nations Office on Drugs and Crime. It has been lauded by academics, policy-makers and the press, with the Financial Times describing it as an "eloquent and campaigning book" and slavery experts heralding it as "groundbreaking" and the "best book yet on the enduring problem of modern-day slavery." The book has become a go-to resource for policy makers, foundations, and NGO's around the world.

In the book, Kara draws on his background in finance, economics and law to provide what is widely considered to be the first ever comprehensive business, economic and legal analysis of modern slavery worldwide, focusing on sex trafficking, its most profitable and barbaric form. He provides a riveting account of his journey into this unconscionable industry, sharing the moving stories of its victims and revealing the shocking conditions of their exploitation. He describes the local factors and global economic forces that gave rise to this and other forms of modern-day slavery across the last two decades and quantifies, for the first time, the size, growth, and profitability of each slave industry. Finally, he recommends the legal, tactical, and policy measures that would target vulnerable sectors in these slave industries, and help to abolish slavery, once and for all.

Kara's second non-fiction book on contemporary slavery, Bonded Labor: Tackling the System of Slavery in South Asia, was released by Columbia University Press in October 2012. It is Kara's second explosive study of slavery, this time focusing on the pervasive, deeply entrenched, and wholly unjust system of bonded labor. While sex trafficking is the most profitable form of modern-day slavery, bonded labor is the most prevalent form.

The book has received high commendations from scholars, activists, non-profit organisations and governments, and was covered as part of a three part series on the CNN International prime time news program Connect the World with Beck Anderson. It has been lauded as "a necessary book for all those concerned with the struggle against contemporary forced labour and slavery" by the International Labour Organisation of the United Nations, "perhaps the most ambitious and reasoned treatment of this form of slavery in the modern era" by Humanity United, "a must-read for all those who work against modern day slavery" by award-winning activist Ruchira Gupta.

In the book, Kara delves into bonded labor to provide one of the first thorough economic, historical and legal overviews of this ancient and ever-evolving mode of slavery, which ensnares roughly six out of every ten slaves in the world. Kara travels to the far reaches of South Asia to uncover the brutish realities of bonded labor in such industries as hand-woven-carpet making, tea and rice farming, construction, brick manufacture, and frozen-shrimp production. He describes the violent enslavement of millions of impoverished women, children, and men who toil in the production of numerous products at minimal cost to the global market. He also follows supply chains directly to Western consumers, vividly connecting regional bonded labor practices to the appetites of the world. Kara's concludes with ten specific initiatives to eliminate the system of bonded labor from South Asia.

Tainted Garments: The Exploitation of Women and Girls in India's Home-Based Garment Sector, is the first ever study of the conditions for home-based workers in India's garment sector. Kara was the lead investigator and author of the report, which was released through the Blum Center for Developing Economies at the University of California at Berkeley in January, 2019. The study found that more than 99% of home-based garment workers were women and girls from minority or outcaste communities who scarcely earned $0.15 per hour producing garments for export to major brands in the West. None of the workers had a contract for their work, and many suffered severe delays in wage payments, chronic ailments, and unfair penalties. Almost one-in five workers were children at the time they were documented, and more than half of the workers began home-based garment work as children. More than 99% of the workers did not receive the minimum wage for their work. The report makes concrete recommendations on how brands can improve transparency and decency in the working conditions for these home-based workers.

Tainted Carpets: Slavery and Child Labor in India's Hand-Made Carpet Sector, is the largest ever study of the conditions of work in India's carpet sector, with over 3,500 cases documented spanning more than 95% of the country's production base. Kara was the lead investigator and author of the report, which was released through the FXB Center for Health and Human Rights at the Harvard School for Public Health in January, 2014. The study found that more than 99% of carpet workers belonged to minority or outcaste communities, and more than 99% of workers did not receive the minimum wage for their work. More than 37% of workers toiled in conditions of forced labor; 28% of workers toiled in conditions of bonded labor; and 20% of workers were children. The report makes concrete recommendations on how the severely exploitative working conditions in India's carpet sector can be improveds.