You mean
this series, Ghost?
Yes, I had the "Clash of the Princes" boxset (translated into Hebrew, even!) when I was 10 or so. I wish I still had them - after their publication in 1986, they were not re-printed, so they are ultra-rare. Still, they are available on Abe Books ... at about $40-50 each, plus tax. (I
said they were ultra-rare, didn't I?)
This series was what introduced me to the fantasy genre in the first place. Looking back, I won't deny it - the books are clearly designed and marketed for children and young adults. There's nothing particularly deep or philosophical about them; there's a clear divide of Good(C) and Evil(TM).

The player, being The Hero(C), is opposed by The Forces Of Evil(TM).
They're gamebooks - that is, by making choices throughout the books, the player turns to numbered entries. Sometimes the entries mean Certain Death(TM); sometimes they mean combat, or A Little Win For The Hero(C).

By collecting a bunch of MacGuffins(C), The Hero(C) eventually reaches The Ending(C), where said MacGuffins(C) can be used in a specific way to clear a way to battle with The Big Villain(TM)!

Presuming that you as The Hero(C) can defeat The Big Villain(TM), you can finish the book and win the game - huzzah!
As you can see, it's fairly simplistic. A step up from the gamebooks is something called Dungeons & Dragons. A step up from D&D is Sir Pterry's deconstruction of D&D, which began with a book called
The Colour of, um ... no, don't help me, tip o' me tongue, starts with M ...