The Book Centurions are the entities manifested in a humanoid centurion-like form created entirely from books. They, however, use magical spears and shields. They can be beaten by either Shock Blasts or Blast Streams.
Realistic Version Information
According to Tobin's Spirit Guide
- Category: Class VI Armored Composite 
- Type: Corporeal (dispersible)
- Attacks: Melee, Range, Rush
- Weaknesses: Proton Stream
- Special: Damage blocking shield
It's not known if the attraction is the books or the actual stored knowledge, but these Class VI entities favor the same book and scroll-filled locations that Paper Constructs are drawn to. Book Centurions are composed of P.K.E.-bonded books and papers, but with a higher book concentration. Most notably, however, Book Centurions carry a distinctive shield, a concentrated P.K.E. barrier that blocks most directed energy attacks. Fortunately, the Capture Stream can still indirectly attack and can be used to tear the shield from the Centurion's hand.
Book Centurions are not much different than Paper Constructs and as such, are susceptible to the same vulnerabilities--namely the Proton Stream and Boson Darts. However, these hardcover haunters carry a protective shield that makes then nearly invulnerable to your initial attacks. Make short work of these paper pests by using your Capture Stream to rip off their shields, then dispersing them with your Proton Stream or Boson Darts.
In addition, flanking the Book Centurions and dispersing them with one or more close range Shock Blasts has also proven effective.
Stylized Version Information
According to Tobin's Spirit Guide
- Category: Class 4 Organic Physical Conglomerate
- Abilities: Flying Ram
Oftentimes, in the vicinity of a ghost with strong psychokinetic abilities, certain small objects will seem to take on a life of their own, moving at the behest of the controlling spectre. It's important to make the distinction between these objects that are being remotely manipulated and those having an actual spectral presence inside them.
Certain conglomerates that I've encountered have not only used their smaller constituent parts to form locomotive elements but arms and armor as well. These usually protect the psychokinetic foci that bind them together.
These are the Gray Lady's middle-of-the-road conglomerates. You need to expose the weak point on their shield and slam it off before you can attack the Book Centurion himself. The Blast Stream and Shock Blast are both good choices for shredding these guys.
The art page can be in the NYC Public Library, during the "Ghoul of Your Dreams..." section. It is hidden inside a grandfather clock near where you attempt to scan the Gray Lady.
Ghostbusters: The Video Game Official Game Guide by Prima suggests that the Book Centurion in the Realistic version is a Class IV in the Tobin's Spirit Guide section of the book , while the video game's Tobin's Spirit Guide states is is a Class VI.  However, later in Checking out the Library chapter of the Prima guide, in the Ghosts Encountered section, it is stated to be a Class IV but in the notes, states it is a Class VI. 
- ↑ Book Centurion Tobin Scan
- ↑ Book Centurion Tobin in Prima's Official Guide
- ↑ Book Centurion Tobin in in the Video Game itself
- ↑ Book Centurion Ghosts Encounter in Prima's Official Guide