ABSTRACT
Being a magus in the most complete sense of the term, John Dee was deeply involved in mathesis, the mystical aspects of number, but his interest in mathematics was practical as well as theoretical. It was Dee's concern for the advancement of applied science that inspired him to write a treatise on the great benefits to be gained from everyday use of mathematics. To make this part of his philosophy readily available to his less learned contemporaries – those mechanicians who would use mathematics in their trades – Dee wrote his ‘Mathematicall Preface’ to Euclide in the vernacular.
