Fionavar Tapestry--should I keep reading?

I loved loved loved The Summer Tree. The trilogy descends into total suck by the last one. Stop now.

I will admit to being annoyed by the Carlo Ginzburg fest in Tigana (I think it was), probably because I’d read The Night Battles not long before.

Is that the bit about the people born with a caul fighting supernatural battles to save the harvest?

I strongly suspected that was based on a real superstition, but had no real clue who held it or when.