The book consists of the lectures presented at the NATO ASI on 'Algebras and Orders' held in 1991 at the Universit? de Montr?al. The lectures cover a broad spectrum of topics in universal algebra, Boolean algebras, lattices and orders, and their links with graphs, relations, topology and theoretical computer science. More specifically, the contributions deal with the following topics: Abstract clone theory (W. Taylor); Hyperidentities and hypervarieties...