Actually it is not at all clear that the Biblical Hittites were the same people as the Anatolian Hittites, the ones who built the dam.The places that the Israelites encountered them don't match up with what is known outside of the Biblical accounts.
Roaring into history from mysterious origins, the Hittites would rule a great empire that stretched from Mesopotamia to Syria and Palestine. The Hittites are shrouded in fog and mystery; we don't where they came from, and for a long time the language they spoke was undecipherable. In the end, it turns out they were Indo-European, that is, they spoke a language from the Indo-European language family, which includes English, German, Greek, Latin, Persian, and the languages of India. Their invasion spelled the end of the Old Babylonian empire in Mesopotamia (1900-1600 BC), and like so many others before them, the invaders adopted the ways of the conquered; after the conquest of Mesopotamia, the Hittites adopted the laws, religion, and the literature of the Old Babylonians thus continuing the long heritage of Sumerian culture.
Their empire was at its greatest from 1600-1200 BC, and even after the Assyrians gained control of Mesopotamia after 1300 BC, the Hittite cities and territories thrived independently until 717 BC, when the territories were finally conquered by Assyrians and others.
The Hebrew scriptures have little to say about the Hittites, and the Egyptians regarded them as barbarians. In fact, from 1300-1200 BC, the Hittites waged a war against Egypt that drained both empires tragically. The Hittites themselves seem to have left few accounts of their history, so until this century no-one really knew their culture or the greatness of their political ascendacy
But the Hittites are perhaps one of the most significant peoples in Mesopotamian history. Because their empire was so large and because their primary activity was commerce, trading with all the civilizations and peoples of the Mediterranean, the Hittites were the people primarily responsible for transmitting Mesopotamian thought, law, political structure, economic structure, and ideas around the Mediterranean, from Egypt to Greece. So the Hittites are the great traders in the culture built by the Sumerians and adopted and modified by later peoples. Because of the Hittites, when the Hebrews migrated to Canaan under Moses they found a people, the Canaanites, who were, culturally speaking, Mesopotamian.
The Hittites greatly modified the system of law they inherited from the Old Babylonians. The most extensive literature that the Hittites have left us is, in fact, decrees and laws. These laws were far more merciful than the laws of the Old Babylonians, perhaps because the Hittites were less concerned about maintaining a rigid, despotic central authority. While you could lose your life for just about everything under the Old Babylonian system of laws, including getting rowdy in a tavern, under the Hittites only a small handful of crimes were capital crimes. Even premeditated murder only resulted in a fine—a large fine, to be sure, but far preferable than losing your head. They modified the role of the monarch in that they gave the king ownership of all the land under his control; previously, under the Sumerians and Amorites, private property was allowed and the monarch only owned his own private property. Individuals were allowed control over land, which belong to the king, only by serving in the king's army. So the bulk of the population became tenant farmers.
The Hittites adopted many of the gods of the Sumerians and Old Babylonians. The odd thing about the Hittites, though, is that they seemed to have recognized that all gods were legitimate gods. Whenever they conquered a people, they adopted that people's gods into their religious system, in much the same way the uji , or clans, in early Japan would adopt the gods of rival uji when they had conquered them. As far as history is concerned, this has tremendous consequences for the history of the Hebrews. The Assyrians seem to have adopted the same tolerance towards other religions, which allowed the Jewish faith to persist after the Jewish state was decimated by the Assyrians. And the Assyrians seem to have adopted the same tendency to adopt the gods of conquered people, so the Assyrian conquerors of Palestine adopted the Hebrew god, Yahweh, into their religion. This eventually led to the only major religious schism in Hebrew history, the schism between Jews and Samaritans (there are still Samaritans alive today).