The 555 timer was created by Hans Camenzind (b. 1934) in 1970 while he was working for Signetics. The design process took about a year. Designing the chip was all done by hand, using rubylith which made the process take much longer than by today's standards.
The 555 timer replaced 23 transistors, 15 resistors and 2 diodes and allowed manufacturers to use this problem solving method much easier.
Today with billions of the chips in exsistence, it is one of the most widely used chips. Most people who do electronics hear of the 555 timer first. It is the gateway drug to the world of integrated circuits.