This dissertation consists of three chapters. The first two chapters explore the economics of child-bride marriage. The third chapter provides an economic analysis of magna carta. Chapter one develops and empirically evaluates an economic theory of the market for child brides---females who begin marital cohabitation before menarche. The theory is grounded in son preference---the preference for male over female children commonly found in developing countries. Son preference generates a supply of child brides when son-preferring couples produce unwanted daughters in their attempt to produce sons and seek to dispose of such daughters via the marriage market. Son preference also generates a demand for child brides when adult males are induced to search for spouses in younger cohorts in the face of an imbalanced sex ratio in the marriage market, caused by differential investments in sons versus daughters by son-preferring couples that encourage the survival of more males than females to puberty. Evidence from India supports the theory's predictions: stronger son preference is associated with the birth of more unwanted daughters, younger postpubescent-female age at marriage, and a higher incidence of prepubescent brides. Moreover, son preference has a stronger positive association with prepubescent brides where poverty is more extreme; prepubescent brides have lower quality husbands than postpubescent brides; and stronger son preference is associated with a higher ratio of traditional-marriage-aged males to females.

Chapter two investigates the effects of policies aimed at raising female marriage age for women in developing countries where parents strongly prefer sons to daughters. I find that raising female marriage age in such countries may have the unintended consequence of increasing the prevalence of female infanticide and sex-selective abortion. Where parents strongly prefer sons to daughters, some parents seek to dispose of their unwanted daughters through child-bride marriage, female infanticide, or sex-selective abortion. By raising the cost of child-bride marriage relative to infanticide or abortion, policies that raise female marriage age may induce such parents to substitute the latter disposal methods for the former. I evaluate one such policy in Haryana, India and find empirical support for this prediction. My analysis suggests that from the perspective of female welfare, child-bride marriage may be a second-best institution, or constrained optimum, in developing countries that exhibit strong son preference.

Chapter three analyzes Magna Carta using the economic approach to self-enforcing constitutions. Reissued, but not original, Magna Carta satisfied each of the conditions necessary for constitutional self-enforcement of the charter according to that approach, and thus an effectively constrained government. This analysis illuminates the original charter's failure to constrain government and its subsequent success in doing so. This analysis also furnishes supportive evidence for the economic approach to self-enforcing constitutions.