2 complete full-length novels.
While most of the earth is submerged under a wave of religious fanatacism and an increasingly authoritarian government, a top secret project on Jupiter unravels the fundamental mystery of gravity. The discovery makes possible the 'spindizzy' field that can nullify gravity, hold in an atmosphere, and make travel faster than light possible. And starships can be as large as the job requires--the size of cities, if necessary.
Encased in their spindizzy fields, the great cities of Earth began deserting the used-up home pplanet and its tyrannical governments to wander the spaces between the suns. But when New York launched itself into interstellar space, it picked up an involuntary passenger. Neither he nor the leaders of the city could have guessed the critical part he would play in thefuture of the spaceborne cities . . .
Blish's scale is the whole galaxy, a view that has to be awe-inspiring if he can only make you se it; and he does!
First novel, THEY SHALL HAVE STARS, has much hard science in it. Second novel, A LIFE FOR THE STARS, more oriented to characterization and personal growth.