This book brings together in one convenient volume eight articles by Professor Nicholas Williams on Traditional Cornish. They include "I-affection in Breton and Cornish" (2007), "The Cornish englyn" (2007), "The preterite in Cornish" (2010), "Some Cornish plurals" (2011), "Adjectival and adverbial prefixes in Cornish" (2013), "'If' in Cornish" (2014), "Reflexive verbs in Cornish" (2014), and "Auxiliary verbs in Cornish" (2016). These are presented in eight chapters; seven deal with various aspects of the historical phonology, morphology and syntax of traditional Cornish. One article examines the Cornish form of the englyn, a three-lined stanza common to both Cornish and Welsh. The first five of the chapters originally appeared as articles in "Cornish Studies". Two further chapters were first given as short papers at the Skians conferences of 2014 and 2015 respectively. The last chapter of the book discusses the auxiliary verbs of traditional Cornish and has not been published hitherto. Because the sections below were written at different times and for varying purposes, there is a certain degree of overlap in their subject-matter. Cornish lacks native speakers, thus revivalists have no one whose pronunciation or idiom can serve as a model for their own speech. It is therefore of vital importance that we who attempt to use revived Cornish should be as familiar as is possible with the traditional language as it survives in the Middle and Late Cornish texts. Indeed reading those texts carefully can be both most instructive. "Studies in Traditional Cornish" is a companion volume to four other works on similar topics: "Cornish Today", "Towards Authentic Cornish", "Writings on Revived Cornish", and "Form and Content in Revived Cornish".