There are four Hebrew letter (Yod, He, Waw and He) called the "Tetragrammaton". The four characters are the four Hebrew letters that transliterate into English IAUE or Yahweh. Yahweh is the name of the Almighty Father in Heaven that people commonly call "The LORD" or "God". The reason we see "LORD" and "God" in our bibles is because of a Jewish tradition that the name Yahweh was not to be spoken for fear that the name be blasphemed. However, this tradition does not agree with the scriptures which declare that His name be exalted! (Ps 68:4 is a good example). The Preface of some bibles will declare why they change His name. Nearly all will cite tradition and familiarity as the reason. The tetragrammaton has been found in the 2,000 year old Dead Sea Scrolls!