Koufax is arguably the greatest lefty ever. His numbers tell the story even taking account the arm injuries that forced him to retire early.
Nevertheless, his stats from 1961 to 1966 are unique in modern baseball.
Overall, he pitched 4 no hitters including a perfect game in 1965;
He won 165 games with a 2.76 ERA;
No one could touch him in the 1963 and 1965 World Series;
Cy Young in 1963, 1965 & 1966; and last but not least,
NL MVP in 1963.
Sadly, arm injuries forced him to retire after 1966 or age 32.
On a personal level, he broke my heart when he beat the Twins in game 7 of the 1965 World Series. We ran home from school to watch that game and LA beat Minnesota behind Koufax's 2-0 performance.
A few years ago, I read this great book about Koufax.