Who Invented Clock and Why ?

I guess technically the first "clock" would have been a sundial which was originally inveted by the early ancient egyptians. There are many forms of clocks since then... like around the 1300’s mechanical clocks which used weights or springs with out a face, no hour or minute hands but struck a bell every hour were there and the slowly later hour hands and minutes hands came in to picture for more precise time measurements... 1400’s coiled springs and mechanical concept of escapement were used and able to move the hands on a clock as well as weights or springs of previous, larger clocks. This discovery made smaller clocks, and later watches, possible. 1600's, Christiaan Huygens invented the pendulum clock, which used weights and a swinging pendulum. These were much more accurate. The bigger the pendulum, the more accurate the clock was. At the dawn of the 20th century, we have wrist watches, digital watches, clock applications on our computers and mobiles... so the technology wheel kept spinning and now we are seeeing this thing called clock in so many forms...and so also its too tough to answer the question who invented the clock, but for your second question there is one obvious answer, why clock is invented - "for time keeping" so that i dont miss meeting my girl friend on time and I dont make ther angry... ;)