In spite of inevitable deficiencies in their knowledge, 17th-century writers on phonetics can be said to have succeeded in laying the foundations of a true general phonetics. They include some famous names, such as John Wallis and Isaac Newton, but many of them have remained virtually unknown until comparatively recent times, in spite of having contributed significant insights. A brief mention is given here of the work of thirteen of these early writers on phonetics, followed by a fuller account of William Holder (1616–1698), probably the best phonetician of his time. He was not an orthoepist, nor was he concerned to describe the sounds of English. His book had a practical purpose – to provide a theoretical basis for techniques of teaching the deaf. Possible ambiguity in the 17th-century use of ‘letter’ is explained before examining Holder’s description of the sounds of speech. This includes his interesting use of the hylomorphic distinction between ‘matter’ and ‘form’. The description of vowels is almost inevitably less satisfactory than that of the consonants, but his phonetic terminology and general framework would not be out of place in a modern introduction to phonetics. He deserves more attention than he has received, both for his theoretical contribution and for his pioneering work in techniques of teaching the deaf.