Certainty is less secure at boundaries, reality less rigid. In places ambiguous (neither sea nor shore, day or night, river or land) magic can seep through.
Work in Progress
Audrey Faye has started an interesting Shifters series, Ghost Mountain Wolf Shifters. So far there are three books in the series, Alpha, Heart, and Rebel. The characters are well-developed, and interesting. Again, books that you will read more than once.