Near Space for Starfinder gives players a detailed look at a fairly dense region of space where hundreds of different worlds lie. If you'd like to get an inside look at what's inside the book (it's in inside-ception!), you can check out this article. It gives you a chapter breakdown of what's coming in the book.
From the post:
Journey to Near Space, the galactic region that contains the Pact Worlds, the Veskarium, and countless other systems and worlds. This hardcover rulebook expands the Starfinder campaign setting with details on dozens of planets and cultures found in Near Space, each perfect as a locale for science-fantasy adventure! Inside this book you’ll find:
In-depth gazetteers of the nine worlds of the Veskarium, the interstellar empire founded by the militaristic vesk, and of 20 more worlds and civilizations of Near Space.
New starship options and a dozen new starships.
A wide variety of new player options: archetypes, themes, gear, spells, and alternate racial options!