Harnmaster is divided into loose leaf articles meant to be placed in a 3-ring binder. There were a few exceptions but the whole line was published like this after the mid 80s.
This is a 2 page article outlining the system and their philosophy. The basic gist is stated in this sentence
HârnMaster is a fantasy role-playing game in which players assume the identities of characters who explore and experience a fantasy world.
The Gamemaster (GM)
Their view of the role of the gamemaster is summarized below
The Gamemaster (GM) is apart from the players and functions much like a referee at a sports event. Among many other things, the GM controls weather and climate, societies and institutions, and deities and religions.
The GM stands between the fantasy world and the players, describing and explaining it, and operating the denizens that hinder the PCs’ lives. But the GM also operates Non-Player Characters (NPCs) who can befriend and assist PCs and should never, therefore, be viewed as the “enemy.”
The introduction also includes this about the players
The players’ challenge is to explore the fantasy world, meet it on its own terms, and succeed according to the goals they set for themselves.
The sidebar explains the other products in the Harnmaster system.
This is a short section explaining all the terms, conventions, and abbreviation used in the rules.
One of the reason I like Harnmaster and product is that their view of how to run a campaign closely aligns with mine. Most of their products I found highly useful for my Majestic Wilderlands setting because of this.