They Shall Have Stars is not a novel so much as a long introduction to James Blish's Okie books. The book's only existence is to show the invention of the antigravity technology and anti-aging drugs that feature so prominently in the sequels. It's no surprise that although chronologically They Shall Have Stars is the first book in the series, it is not the first book that Blish wrote. I doubt it would have been published if not for the reputation of the rest of the series. Then again, standards were lower in 1960s.