how coilovers work?

[playastarkz123]

Now i know that this thread makes me seem like an extreme newb but i have been searching for awhile and couldnt find what i am lookin for.

what i want to know is exactly how do coilovers work. I know that the purpose of coilovers is to lower the car and and stiffen the chassis in order to prevent body roll, but how is this accomplished? I hear people on the boards use words like "valving", what is this and what is its purpose?

Besides levels dampening and height adjustment, and i guess durability what makes one coilover better than another?

just tryin to learn more, thats all, please no stupid comments.