The history of EM is a vast subject. How does one organize one's approach to studying it? Alternatively, what themes can serve as a framework for approaching study of it?
There are many ways to do so. Below are two that inform this library guide. Other approaches are available, e.g., one can look at the history of how physicists conceptualized analogies or disanalogies between disparate phenomena: electricity, magnetism, thermodynamics and gravitation. Or look at the role mathematics played in the development of EM throughout its history.
Two approaches (largely) taken in this guide focus on:
1.The Lead-up to Maxwell's Equations
The long and complicated lead-up to Maxwell's famous electromagnetic equations, now summarized as four, provides a way to organize one's understanding of the antecedent tradition of theorizing about electromagnetism (EM), from the standpoint that these equations crystallize or synthesize developments prior to Maxwell.
See the section of this guide about Maxwell for links to articles that provide background about this pre-Maxwell work in EM. The section includes a timeline of developments in EM.
2.The "Ether" and "Action at a Distance"
A second way to organize one's understanding of this history is to look at ways physicists addressed the question: what is the medium or substrate--or the mechanical mode of action--for transmitting electricity and magnetism? This question hearkens back to a larger question posed by Aristotle: can nature contain a vacuum, or is nature a plenum?
With the advent of modern science, from the very early 17th century onward, if not before, theories about the action of forces, not just in relation to electrical or magnetic phenomena but also gravitational, took sides (implicitly or explicitly) on the question whether forces involve "action at a distance" or whether forces act through a medium.
In the context of nineteenth century electromagnetic theory, there was significant debate concerning one possible medium, the so-called "ether": whether it exists, how to characterize it if so, and whether physics should just remain agnostic about its existence but still do its work.
Einstein's theory of special relativity challenged the concept, implicit in at least some concepts of the ether, that there is an absolute reference frame. The Michaelson-Morley experiment debunked the latter concept. But there is a question whether in his later work, Einstein re-admitted a concept of the ether. And what can we make of this concept, or conceptions of the "vacuum", in more recent physics?
The debates surrounding the ether provide good examples of how one idea can take various forms throughout history. The guiding question for this approach to history of EM is: what are the commonalities and differences in ways the question about the medium for EM activity has appeared in the history of physics?
The section of the guide titled Resources: History and Philosophy of Electromagnetism provides resources that address this second approach to organizing one's understanding of the history of physical theorizing and experimentation about EM. More generally, it has links to material about the philosophy of science, as the history of EM provides a kind of "laboratory" for testing out hypotheses, e.g. relating to the instrumentalism versus scientific realism debate.
Finally, the guide links to materials relating to the role of history of science in learning and teaching science. The history of research about EM provides an excellent case study in how knowledge of the genesis of concepts in a particular field helps enliven one's understanding of it. Moreover, it leaves one impressed by how philosophical and historical understanding of the history of physics can provide one tributary (among others) leading to new advances.