Here is what is says about Rangers for the Introduction of Ranger's handbook.
The ranger is one of the most popular character classes in the AD&D® game. A woodsman and tracker, as well as a dangerous fighter, he combines good combat skills with a few extra abilities that give him many options and decisions during play. He boasts the courage and strength of a warrior and the stealth and self-reliance of a thief. He combines the druid's affinity for the outdoors with the devotion and magical aptitude of a priest. He's a hunter, a tracker, and a survivalist. By temperament and by choice, he's a loner, often preferring the company of animals to people. Without question, he's one with nature, sworn to protect the inhabitants of the wilderness and preserve the integrity of the land.
The ranger's origins can be traced to the time when isolated human settlements were first founded in areas of unclaimed wilderness, or in areas occupied only by savage humanoid tribes. Those who were at first hunters, trappers, and guides were turned by the necessities of survival into canny wilderness warriors; and ultimately into the principle protectors of the scattered settlements of humans and demihumans, which had to fend off countless humanoid raids.