,,itwas(andstillis)animportantformofgovernanceinagriculture,,sharetenancycontractsdisplayproblemstypicalofabroadspectrumofcontractualarrangements:todaytheseproblemsareoftendiscussedunderthe“principal-agent”,previousconclusionsonsharetenancyseemedtoosimple,evensuspect:,toasignificantextent,'sgraspofthelargeliteratureonsharecropping,hiscarefulanalysis,:theresultsofliterallyallpreviousstudieswereunconvincing,-blowtothehabitofeconomistsofdeclaringasituationinefficient,,,,,,,,Idecidedtousestandardeconomicprinciplestoformulatehypothesesrelatingtosharetenancy（orsharecropping）.Havingpletedthefirstdraftofmythesis,however,,sharetenancyhaslongbeenconsideredinefficient,,,"irrational"behaviorhasbeendiscerned,andspecialtheoriessuchas"disguisedunemployment"andthe"dualeconomy",however,,,Iseektoexplain（1）whythepatternsofagriculturaloutputdifferundertwosetsofpropertyrightconstraints,and（2）,,MasonGaffney,JudithMann,,thenacolleagueatCaliforniaStateCollegeatLongBeach,,.Chapter4waswrittenlast,,HaroldDemsetz,JohnMcManus,,PatriciaKuttner,,includingtheSino-AmericanJointCommissiononRuralReconstruction,theTaiwanProvincialLandBureau,theDepartmentofAgricultureandForestry,,asdidtheorientallibrariesatBerkeley,Stanford,UCLA,andChicago.