Skylark Three: Skylark of Valeron by E.E. Doc Smith

Paperback. Condition: Good+. 1979. Panther.

As the mighty spaceship Skylark roved the intergalactic world, scientist Richard Seaton and his companions uncovered a world of disembodied intelligences. A world of four dimensions where time was insanely distorted and matter obeyed no terrestrial laws... where three-dimensional intellects were barely sufficient to twart invisible mentalities!