Siddhartha

by Hermann Hesse

was it valuable to know all of this, not knowing that one and only thing, the most important thing, the solely important thing?

I translated it just a bit differently: ...was it worthwhile to know all this, if one did not know the One and Only, the most important, the only important thing?

It had to be found, the pristine source in one's own self, it had to be possessed! Everything else was searching, was a detour, was getting lost.

Again, my reading is a tiny bit different: One had to find it, the source within oneself, one had to possess it. Everything else was searching, a diversion, an aberration (illusion).