Hmmm your question is too general. Perhaps you can start with buying electronics books. Nowadays IC is everywhere in electronics. From my understanding, IC is a mini circuit which consists of collection of semiconductor devices.
Let me Google that for you Is it just me or anyone else think that some people are really getting too dumb to search?
Integrated Circuits are usually called ICs or chips. They are complex circuits which have been etched onto tiny chips of semiconductor (silicon). The chip is packaged in a plastic holder with pins spaced on a 0.1" (2.54mm) grid which will fit the holes on stripboard and breadboards. Very fine wires inside the package link the chip to the pins.
HELLO An integrated circuit or monolithic integrated circuit is an electronic circuit manufactured by the patterned diffusion of trace elements into the surface of a thin substrate of semiconductor material. and it is used in virtually all electronic equipment today and have revolutionized the world of electronics.
IC stand for Integrated Circuit and ever since the VLSI Technology was created everything electronics become possible to developed. VLSI stand for Very Large Scale Integration. Simply put it thousand of very small transistor can be created in a very small package.