The United States introduced the earned income tax credit (EITC) in 1975, where it remains the most significant earnings-based refundable credit in the Internal Revenue Code. While the United States was the first country to use its domestic revenue system to deliver and administer social welfare benefits to lower-income individuals or families, a number of other countries, including New Zealand and Canada, have experimented with or incorporated similar credits into their tax systems. In this work, Michelle Lyon Drumbl, drawing on her extensive advocacy experience representing low-income taxpayers in EITC audits, analyzes the effectiveness of the EITC in the United States and offers suggestions for how it can be improved. This timely book should be read by anyone interested in how the EITC can be reimagined to better serve the working poor and, more generally, whether the tax system can promote social justice.