\noindent
{\bf Electromagnetism} is the science of electric and magnetic
fields and of the interactions of these fields with electric
charges and currents.

\section{Introduction}

Electromagnetism is one of the fundamental interactions of nature.
Its physical origin lies in a property possessed by elementary
particles of matter---electrons and protons---called electric charge.
The electromagnetic interaction also governs light and other forms
of radiation.
Electricity and magnetism appear in many natural phenomena,
and are applied in many inventions of technology
and everyday life.
The purpose of this article is to describe the basic science
and applications of electromagnetism.

The earliest discoveries of electric and magnetic forces
were made by philosophers of ancient Greece.
They observed that when amber is rubbed with animal fur, it acquires the ability to attract small bits of reed or feathers.
This small effect was the first observation of static electricity.
(The Greek word for amber,
$\epsilon\lambda\epsilon\kappa\tau\rho{o}\nu$,
is the origin of our word ``electric.'')
They also observed that a lodestone exerts a force on
iron---the first example of magnetism.
(The Greek province of Magnesia, where the iron ore magnetite
occurs naturally, is the origin of our word ``magnetic.'')
These discoveries of weak and mysterious forces were the
first steps toward our scientific understanding of electromagnetism.
Today science has dispelled much of the mystery of
electricity and magnetism,
and created technological power beyond the dreams
of the ancient philosophers.