This study provides the first description-oriented, theoretically-unaligned account ofwh-clauses in Modern English. The author employs a data-based approach to examine aspects of both generative and non-generative work as regards their relative strengths and weaknesses. Wh-clauses in English: Aspects of Theory and Description is a unique combination of statistical findings and qualitative analysis. It is not only underpinned by a systematic investigation of the Brown University corpus but also includes attested material from other sources such as the British National Corpus, the CobuildDirect corpus as well as material gleaned from the internet. The qualitative and quantitative analyses are combined to approach a wide range of theoretical and descriptive issues, such as wh-movement, landing-sites for moved wh-XPs, vacuous movement, island constraints, among others. Not insignificantly, many questions of indeterminacy are addressed, such as the interface of conjunctions and relative words, the problems of demarcation between interrogatives and free relatives as well as structural ambiguities between interrogatives and exclamatives.