Joseph Larmour (1857–1942) was a theoretical physicist who made important discoveries in relation to the electron theory of matter, as espoused in his 1900 work Aether and Matter. Originally published in 1929, this is the first part of a two-volume set containing Larmour's collected papers. The papers are presented in chronological order across the volumes, enabling readers to understand their theoretical development and framing them in an accessible form for 'future historical interests'. Authorial notes and appendices are also included. This book will be of value to anyone with an interest in the word of Larmour, mathematics physics and the history of science.