for cliometrics. Slavery and Time on the Cross Fogel's most famous and controversial work is Time on the Cross (1974), a two-volume quantitative study of American slavery, co-written with Stanley Engerman. In the book, Fogel and Engerman argued that the system of slavery was profitable for slave owners because they organized plantation production "rationally" to maximize their profits. Due to economies of scale, (the so-called "gang system" of labor on cotton plantations), they argued, Southern slave farms were more productive, per unit of labor, than northern farms. The implications of this, Engerman and Fogel contended, is that slavery in the American South was not quickly going away on its own (as it had in some historical instances such as ancient Rome) because, despite its exploitative nature, slavery was immensely profitable and productive for slave owners. This contradicted the argument of earlier Southern historians. A portion of Time on the Cross focused on how slave owners treated their slaves. Engerman and Fogel argued that because slave owners approached slave production as a business enterprise, there were some limits on the amount of exploitation and oppression they inflicted on the slaves. According to Engerman and Fogel, slaves in the American South lived better than did many industrial workers in the North. Fogel based this analysis largely on plantation records and claimed that slaves worked less, were better fed and whipped only occasionally – although the authors were careful to state explicitly that slaves were still exploited in ways which were not captured by measures available from records. This portion of Time on the Cross created a firestorm of controversy, although it was not directly related to the central argument of the book – that Southern slave plantations were profitable for the slave owners and would not have disappeared in the absence of the Civil War. Some criticisms mistakenly considered Fogel an apologist for slavery. In fact, Fogel objected to slavery on moral grounds; he thought that on purely economic grounds, slavery was not unprofitable or inefficient as previous historians such as Ulrich B. Phillips had argued. Without Consent or Contract: The Rise and Fall of American Slavery In 1989 Fogel published Without Consent or Contract The Rise and Fall of American Slavery as a response to criticism stemming from what some perceived as the cold and calculating conclusions found in his earlier work, Time on the Cross. In it he very clearly