OPENING STATEMENT - VOLUME I: This two-volume set of studies takes as its starting point an old idea: the idea that universal grammar is based on meaning. It seeks to give this idea a solid theoretical foundation, and to explore its viability through detailed empirical studies in a set of typologically divergent languages (Lao, Malay, Mandarin Chinese, Mangaaba- Mbula, Polish and Spanish). As the twentieth century recedes, linguists seem increasingly to agree that the "anti-semantic turn" inaugurated by Leonard Bloomfield and continued by Noam Chomsky was a wrong turn. It is now widely believed that the grammatical properties of a word follow, at least in large measure, from its meaning. PREFACE TO VOLUME II: This set of studies is founded on the idea that universal grammar is based on - indeed, inseparable from - meaning. The theoretical framework is the natural semantic metalanguage (NSM) approach originated by Anna Wierzbicka over thirty years ago and developed since then in collaboration with Cliff Goddard and other colleagues. ... The NSM framework is based on evidence supporting the idea that there is a set of simple, indefinable meanings - universal semantic primes - which have concrete linguistic exponents in all world's languages. The NSM system is perhaps best known as the methodology for a large body of descriptive studies in cross-linguistic semantics and pragmatics, but it also has fundamental implications for the theory of universal grammar. The key idea is that universal semantic primes have an inherent grammar (including combinatorics, valency and complementation options) which is the same in all languages.