These notes are pretty "skimmable" http://www-control.eng.cam.ac.uk/~mcs/lecture_j.pdf

My own experience... I know why this concept sounds so familiar to me. I had one when I was little.

There are many childrens toys with a flywheel and a ripcord. That system is an "Inerter"... If the ripcord is a rigid toothed rack and pinion setup then it can act as an "Inerter" in compression as well as tension.