Who is Prophet Muhammad?
Muhammad, was born in Makkah in the year 570. Since his father died before his birth, and his mother shortly afterwards, he was raised by his uncle from the respected tribe of Quraysh. As he grew up, he became known for his truthfulness, generosity and sincerity, so that he was sought after for his ability to arbitrate in disputes. The historians describe him as calm and meditative.
Muslims belive Prophet Muhammad is the last prophet in a long line of prophets which include, Adam, Abraham, Moses, Jesus, etc. The sayings of Prophet Muhammad are called "Hadith". They are another source of religious instruction used by Muslims in addition to the Quran. The words of the Quran, however, are infalliable (as the direct words of God) and unchanged since they were first related. Hadith texts, on the other hand, can contain errors, thus making sure they come from a valid source is important practice.
First paragraph taken from:http://www.islamicity.com/prophetmuhammad