Horos markers were used to indicate when a property was mortgaged and who the creditors were. This study publishes known examples from ancient Athens and explores how the mortgage system may have worked. The book contains eight chapters: Chapter I presents 35 new horos mortgage inscriptions. Chapter II contains references to, or transcriptions of, all other known horos mortgage stones. Chapter III is devoted to a discussion of the use and physical properties of stone horoi and to the possible use of wooden horoi. Chapters V to VII provide careful analyses of the various kinds of contracts drawn up by the Athenians when the security consisted of real property. Chapter VIII attempts to date the introduction of mortgage contracts at Athens and to explain the lateness of this date—the earliest horos example probably dates to after the Peloponnesian War.