Sumário:The initial law and economics approach; social; the moderns law and economics approach -- The modern view : interest rates and investment : bankruptcy systems and the interest rate; interest rates and investment : funding efficient projects; pursuing projects efficiently; summary -- Mandatory versus default systems : soft or tough procedures; the bankruptcy initiation problem; the state dependency problem : state dependency; contracting over bankruptcy systems; impediments to bankruptcy contracting; Ex post contracts -- Contracting out of a bankruptcy system.