Semanticswillhaveanimportantroletoplayinthefuturedevelopmentofsoftwaresystemsanddomainspecificlanguages,andthereisarealneedforanintroductorybookthatpresentsthefundamentalideasbehindtheseapproaches;stressestheirrelationshipbyformulatingandprovingtherelevanttheorems;andillustratestheap