Colonizations

In Tales Of The Flying Mountains (New York, 1984), people from Earth use gyrogravitics to terraform and colonize asteroids and to move one terraformed asteroid towards Alpha Centauri whereas, in The Earth Book Of Stormgate (New York, 1979), human beings and Ythrians, having crossed interstellar space by hyperdrive, colonize the terrestroid planet Avalon.

Tales is seven stories and additional passages collected in 286 pages whereas the Earth Book is eleven stories and one novel with additional passages collected in 434 pages and is just one volume of a much longer series.

Tales focuses entirely on gyrogravitics and asteroids whereas only five of the twelve works in the Earth Book feature Ythrians and only three feature Avalon although the additional passages are fictitiously written by an Avalonian Ythrian whereas the additional passages in Tales are dialogues inside the asteroid moving to Alpha Centauri.