Abstract. Defeasible logics are non-monotonic reasoning systems that have efficient implementations and practical applications. We list several desirable properties and note that each defeasible logic fails to have some of these properties. We de?ne and explain a new defeasible logic, called clausal defeasible logic (CDL), which has all these properties. CDL is easy to implement, consistent, detects loops, terminates, and has a range of deduction algorithms to cater for a range of intuitions.