This book presents a development of Jean Lowenstamm's idea that phonological constituent structure can be reduced to a strict sequence of non-branching Onsets and non-branching Nuclei. The approach at hand is known as 'CVCV', and emerged from Government Phonology. Since its beginnings in the early 80s, the central claim of this theory has been that syllable-based generalisations are due to lateral relations among constituents, rather than to the familiar arboreal structure. The theory developed completes this approach: phonological structure and causality are fully lateralised. The first part of the book is called "What is CVCV ?". It presents the properties of the theory. The second part focusses on the reasons why it is worthwhile considering CVCV a valuable and viable approach.