This book is the only comprehensive analysis of contemporary prison labor in the United States. In it, the author makes the provocative claim that prison labor is best understood as a form of slavery, in which the labor-power of each inmate (though not their person) is owned by the Department of Corrections, and this enslavement is used to extract surplus labor from the inmates, for which no compensation is provided. Other authors have claimed that prison labor is slavery, but no previous study has made a rigorous argument based on a systematic analysis of the flows of surplus labor which take place in the various ways prison slavery is organized in the US prison system, nor has another study systematically examined 'prison household' production, in which inmates produce the goods and services necessary to run the prison, nor does another work discuss state welfare in prisons, and how this affects prison labor. The study is based on empirical findings gathered by the author's direct observation of prison factories in 28 prisons across the country. This book offers new insights into the practice of prison labor, and should be read by all serious students of American society.