...I twas a challenge to find the thread that tied them all together, before the author revealed it, of course.
For a book whose thread is a challenge to find, try the Silmarillion. The overarching story will finally become apparent as (and if) you complete your second or third reading. Then you will struck by its intensity. For the next six months you will see life paralleling one part or another of it.
YMMV, of course. It isn't for the faint-hearted. It ain't light reading.