The theory of collective choice belongs to several disciplines. Economics is one of them but not the only one .. While this book
is part of a series in "mathematical economics texts," no attempt has been made to confine the treatment to economic problems exclusively. Indeed the approach of this book is based on the belief. that the problem cannot be satisfactorily discussed within the confine of economics. While collective choice is a crucial aspect of economics (notably of welfare economics, planning theory and public economics), the subject relates closely to politic;at·science. in particular to the theory of the state and the theory of decision procedures. It also has important philosophical aspects, re.lated to ethics and especially to the theory of justice.