How the orientation of an electromagnetic wave changes what light can do and reveal.
What is polarization of light?
Light is an electromagnetic wave. Polarization describes the direction and pattern of its transverse electric-field oscillation.
Unpolarized light contains many orientations. A linear polarizer transmits one component and absorbs or redirects the rest.
What can polarization reveal?
Two polarizers can transmit an amount that depends on their relative angle. Materials can rotate, delay or selectively absorb different polarization states.
Polarization therefore reveals stress, crystal structure, surface properties, scattering and magnetic effects.
Why is it useful?
Polarization is used in sunglasses, displays, microscopy, astronomy, fiber communication, remote sensing and precision instruments.
It also matters in antennas, because radio waves have polarization too.
Future
Polarization-sensitive cameras, integrated photonics and quantum communication will use this degree of freedom more actively.
The basic lesson is that a wave carries more structure than its intensity alone reveals.
Ai disclosure: written with the help of AI (ChatGPT). You are encouraged to point out errors and omissions.  
