Applied Materials (AMAT 4.28%) is one of the most important companies you may have never heard of before. The semiconductor equipment maker -- don't worry, we'll explain what that is -- has posted phenomenal returns for long-term shareholders. Shares are up an astonishing 615,000% since its IPO in 1972, meaning every $1,000 invested at the IPO is worth over$6 million today.With its dominant position in the semiconductor equipment market, a lot of these returns have come in the last five years, with shares ...