This book investigates the nature of fixed expressions and idioms in the English language by challenging traditional definitions through empirical corpus analysis. Rosamund Moon, an expert in lexicography, utilizes a massive dataset of contemporary English texts to demonstrate that idioms are not static entities but dynamic components of discourse. She argues that existing linguistic models fail to account for the contextual variability of these expressions, necessitating a shift toward usage-based frameworks that prioritize how language is actually deployed in real-world communication.

Experts in the field of linguistics recognize this work as a foundational text for understanding the intersection of corpus data and phraseology. Readers frequently note the academic density of the prose, which serves as a rigorous resource for students and scholars of English lexicography.