The Gate of the Cat — Andre Norton

Come. Step through an ancient arch in the Scottish highlands--and into a world beyond all earthly possibilities ...

Where fearsome creatures abound and witches rule supreme.

Where a sparkling jewel carries a strange and awesome power.

Where the terrifying forces of the Dark ravage the countryside.

And where a young Earth woman named Kelsie McBlair holds the key to Witch World's future. Trapped in a bizarre web of science and sorcery, she alone can pierce the savage heart of evil ... by confronting the lord of the Dark himself!