Rudolf Klein's article not only brings together many current theories of policy analysis and of public expenditure but also creates the anxiety that the use of phrases such as ‘public expenditure’ might turn what are obstinate and worthwhile issues into abstractions. Klein's opening statement that ‘public expenditure is quite the most visible and quantifiable measure of government activity’ gives us due warning that public expenditure is being regarded as an independent category, the characteristics and behaviour of which are capable of definition and analysis in their own right. But public expenditure is meaningful only if it is treated as a summation of multiple decisions (and on one dimension only) and of institutional relationships.