I think it's important to get a conceptual grasp of electromagnetism before moving on to say the quantum of quantum mechanics, particles, and gravity. I'd say there's rather more synergy here than is commonly appreciated. Here's a little history to get this across:
Einstein won his Nobel prize primarily for his 1905 photoelectric paper "On a Heuristic Viewpoint Concerning the Production and Transformation of Light". This established the quantum nature of light. Another 1905 paper was "On the Electrodynamics of Moving Bodies". This is electrodynamics and refers to Maxwell, but is considered to be Einstein's special relativity paper. Another important paper was "Does the Inertia of a Body Depend Upon Its Energy Content?" concerning energy and mass. This is where Einstein refers to a body losing mass via radiation, and where E=mc² comes from. He’s mainly remembered for gravity and The Foundation of the General Theory of Relativity (3.6Mbytes), and there's a tendency to overlook the fact that that he was in on the ground floor of quantum mechanics in 1905, and a tendency to overlook the electromagnetism content. People tend not to hear about things like his 1920 Leyden Address where he said this:
Einstein wrote:Of course it would be a great advance if we could succeed in comprehending the gravitational field and the electromagnetic field together as one unified conformation. Then for the first time the epoch of theoretical physics founded by Faraday and Maxwell would reach a satisfactory conclusion.
Some people even think he was against quantum mechanics, but he wasn't, he was against the "spooky" Copenhagen Interpretation, that's all. He was still centre stage at the 1927 Solvay Conference, which discussed the Copenhagen Interpretation. Einstein essentially lost the argument:
After this he was still lauded by the media and public, but became somewhat detached from quantum mechanics, which then morphed into quantum field theory, quantum electrodynamics, and so on. Anyhow, Einstein ended up as "trophy" at Princeton, largely out of the mainstream, still trying to unify electromagnetism and gravity to come up with a unified field theory. Electromagnetism was always very important to Einstein. He had pictures of Faraday and Maxwell on the wall of his study. I was a little surprised when I learned about this, and would say it's an example of how reading material yourself can put a different slant on things. You start noticing things, like a little something in Minkowski’s Space and Time paper from 1908. Most people are aware that this constituted an important development for special relativity. However very few people pay much attention to this little paragraph two pages from the back:
Minkowski wrote:"Then in the description of the field produced by the electron we see that the separation of the field into electric and magnetic force is a relative one with regard to the underlying time axis; the most perspicious way of describing the two forces together is on a certain analogy with the wrench in mechanics, though the analogy is not complete".
It isn't online as far as I know, but see page 73 of The Principle of Relativity: A collection of Original Memoirs on the Special and General Theory of Relativity. You scratch your chin and wonder about this wrench, then you read some original Maxwell. It's rather different to what is described as Maxwell's Equations. I presume that's because "Maxwell's Equations" aren't really Maxwell's equations, because Heaviside rewrote them in vector form. Maxwell wasn't talking about vector fields. His seminal paper is On Physical Lines of Force. On page 53 he says this:
Maxwell wrote:A motion of translation along an axis cannot produce a rotation about that axis unless it meets with some special mechanism, like that of a screw.
He's talking about a screw mechanism, which is what Minkowski's wrench was all about - a wrench turns a bolt, which has a screw thread. And look at the page heading. It's The Theory of Molecular Vortices. Maxwell was suggesting that the electromagnetic field was a sea of vortices, and particles moved through it. This picture is a reproduction of one in On Physical Lines of Force:
If you're anything like me you're saying Huh? What? Why is this so different to what I was taught? Then you read things like A Circular History of Knot Theory mentioning Kelvin's theory of vortex atoms. After a while it sinks in what Maxwell was talking about, and then you realise he missed a trick. He got it back to front. Here's why.