I'll have to check out Susan Cooper's books.
I have been reading
Glen Cook's Black Company series and have finished the first four. Like the Silmarillion, the first one is a bit hard to start, but after getting through the first couple chapters it went well. Even learned a new card game from these books. I am currently reading Bleak Seasons, which is book 1 of the 'Glittering Stone' series. May be a bit dark for some who prefer the lighter Tolkienesque fantasy, but well worth the read in my opinion. Kudos to Moonbiter who prompted me to started reading them a few years back, though I didn't start until last year.