What does an Integrated Circuit do?

Question

What does it do and why is it so important?
Also, who is most responsible for its invention and when was it built.

Answer 1

Whatever it's designed to do.

An integrated circuit is simply a bunch of semiconductors, passive elements (like resistors and capacitors) and conductors all arranged on a single substrate.

They are important because they allow devices to be made smaller and faster (and more rugged, easier to fix, and a number of other reasons).

Jack Kilby at Texas Instruments and Robert Noyce at Fairchild each received a patent for the integrated circuit.