This book is the first volume specifically devoted to the phonetics and phonology of geminate consonants, a feature of many of the world's languages including Arabic, Bengali, Finnish, Hungarian, Italian, Japanese, Malayalam, Persian, Saami, Swiss German, and Turkish. While the contrast between geminate and singleton consonants has been widely studied, the phonetic manifestation and phonological nature of geminate consonants, as well as their cross-linguistic similarities and differences, are not fully understood. The volume brings together original data and novel analyses of geminate consonants in a variety of languages across the world. Experts in the field present a wide range of approaches to the study of phonological contrasts in general by introducing various experimental and non-experimental methodologies; they also discuss phonological contrasts in a wider context and examine the behaviour of geminate consonants in loanword phonology and language acquisition. The volume takes an interdisciplinary approach, drawing on experimental phonetics, theoretical phonology, speech processing, neurolinguistics, and language acquisition.