Is that the whale one? I loved that book when I was a kid! And, yes, it made me bawl, too :)
Yup, that one. I loved all three of the originals (and the assorted sequels, just not as much) but Deep Wizardry is wonderful! Not to mention a really, really sneaky way to get the concept of redemption and sacrificial love across to my assorted Wiccan friends. :-)