Copyright © Harold Aspden, 1972

This book is still in print. Although 2,000 copies were printed, 1,000 bound in hardback and 1,000 in softback, some few of both version still remain unsold, possibly because of the choice of title.

The book is presented in these web pages in PDF (Portable Document Format) and may be read, section by section, according to the following content list. It is suggested that the back cover should be read first.

Title pages
Back Cover
Chapter 1: Nature's Unseen World
Chapter 2: 'The Flight of the Thunderbolts'
Chapter 3: Discovering Gravitation
Chapter 4: The Lodestone
Chapter 5: The Origin of the Solar System
Chapter 6: The Perturbation of Venus
Chapter 7: Microscosmic Foundations
Chapter 8: The Law of Force
Chapter 9: Boundaries of Relativity
Chapter 10: Dirac's Electron
Chapter 11: The Nature of Mass
Chapter 12: The Aether in Evidence
Chapter 13: Action at a Distance
Chapter 14: The Nuclear Aether
Chapter 15: The Earth's Electricity
Chapter 16: The Cosmic Aether
Appendix: The Law of Electrodynamics