Evolution of the concepts of atom and atomism, and the impact of electromagnetism on our worldview, is the object of our study in this book. Electromagnetism is the key link in the transition from classical to post-classical worldview. This transition is caused by the one from our thought based upon the tangibles to that based upon the intangibles. Electromagnetism inaugrated an era of light speeds and near it, and of the world constituted by such speeds. Philosophy and the worldview need to catch up and undergo a basic change. Atom as a concept and reality is under severe stress as explanation of reality. Reality has come out of atomic limits and unveiled a new world, which is constituted of quantum, relativity, wave/particle duality, etc. It is a challenge to philosophy, which re-fashioning to interpret the post-classical world based on rapid motions. We need to develop new concepts and bring about a realignment in various thought constituents. Rather thatn 'overthrow' matter, we are delving deeper into it. Philosophy and human thought itself stands on the brink of redefinition. In the present book the author shows how electromagnetism connects classical with post-classical thought, creating new structures, and impacting materialism and dialectics. This book is co-published with Aakar Books, New Delhi. Taylor & Francis does not sell or distribute the print versions of this book in India, Pakistan, Nepal, Bhutan, Bangladesh and Sri Lanka.