This book "supplies a vocabulary of English words and idiomatic phrases 'arranged … according to the ideas which they express'. The thesaurus, continually expanded and updated, has always remained in print, but this reissued first edition shows the impressive breadth of Roget's own knowledge and interests."
In word formation, the French suffixes -ment and -age have similar meanings (e.g. gonflement - swelling, gonflage - inflating). This book analyses the abstract meaning of the two suffixes and shows their systematic differences at an abstract semantic level. As its starting point it considers the speaker's knowledge and the criteria by which these suffixes are used to form derivations.