Blind Spot Series by Austin Hall

What is 'The Blind Spot?' A room in San Francisco where strange things happened -- a doorway into another cosmos, a different world, perhaps a key to the past... or future? The Blind Spot is a sci-fi novel dealing with the notion of an interdimensional doorway between worlds. When communication is established between the worlds, the results are nothing short of startling! The Blind Spot has been called "the most famous fantastic mystery of them all."

The doorway between the worlds -- the mysterous room where two things could occupy the same space -- had been locked forever, or so its scientist-guardian thought. But nobody had reckoned with the cunning brain of the ruler of that Other World. His advisers had also been working on the dimensional mystery, and they were ready at last. To open up the Spot of Life, to plunge through into the heart of a great American city with an army of unearthly terrors... moreThe doorway between the worlds -- the mysterous room where two things could occupy the same space -- had been locked forever, or so its scientist-guardian thought. But nobody had reckoned with the cunning brain of the ruler of that Other World. His advisers had also been working on the dimensional mystery, and they were ready at last. To open up the Spot of Life, to plunge through into the heart of a great American city with an army of unearthly terrors. And for them, H-Hour was a matter of minutes away! less