In-Game Publications?

[Nytmare]

My current campaign does not, but that's because it's set in a post apocalyptic bronze age where the bulk of written material is on clay tablets. Words printed on linen and papyrus exist, but only as mostly indecipherable text found in ancient ruins.

 

[aramis erak]

Is there any evidence in the core rules that the printing press (mechanical or magical or whatever form) has been invented in D&D? Whether or not there is info in the core rules on this device, does it exist in your D&D campaign?

How much information about the D&D world is available in printed form to people in that world?

Is there a listing of the known monsters in written/published form -- a "Monster Manual"?

Is there a guide book to the different realms?

Is there a guide book to the underdark?

Is there a scholarly work on the various dragons -- a "Draconomicon"?

According to the game books, there exists a "Book of Vile Darkness" and a "Book of Exalted Deeds" in the game world.

Is there an encyclopedia of the various planes of the great wheel -- a "Manual of the Planes"?

My read of both FR and GH, and my homebrewed worlds for D&D, there are monster bestiaries, including draconomicon, there are books covering the various realms and planes, and upon the underdark... but they're all copied by hand or by autoquill, not by printing press, and cost a small fortune.

What info on the world is readily available to people in your world?

Readily available? news via the town crier, articles behind glass at various major towns, and the rumor mill.
Price matters — reasonably accurate if a few years old data is readily available to the wealthy.

Are there books of information useful to adventurers? Are their periodicals? Newspapers?

Quasqueton

There are academic works and practical tomes about various useful things, but they are expensive.

Outside D&D...
WFRP, the printing press is present, and all the various types of books are present - still pricey, but an order of magnitude less expensive than in D&D. Plus, yes, periodicals exist, and newspapers, too - mostly weekly.

given my other common fantasy settings are mouseguard and arrowflight...
Arrowflight - yes, it's renaissance. Printing press in full but still expensive swing
Mouse Guard - essentially dark ages, so while the types of books exist, no major periodicals, hand copied texts.

L5R has some printing, but it's immovable type - hand carved pages for woodblock print. the plates for a book are often woodblock. Some are acid reaction copperplate, so written by hand, then destructively copied to the plate, and the resulting plate being good for a few dozen copies. Only a few books are widely printed: Shinsei's Tao of Shinsei, Akodo's Leadership, Isawa's Elements, a handful of bestiaries... most by raised carved type techniques both wood and metal. Most major clans have a book or two in print for internal use.

 

[jdrakeh]

I once ran a D&D campaign based on PCs working as travel writers for the world's most popular adventure journal. Inspired by Vernor Vinge's Tatja Grimm's World.

 

[Brendan Byrd]

Mystara: Poor Wizard’s Almanac I-III; Joshuan’s Almanac

Darak’s Thaumaturgical Printing Press (AC11, 28)

 

[Deset Gled]

My default setting:

No printing press, no firearms, no antibiotics.

Just scrolls, laser guns, and healing spells.

 

[Brendan Byrd]

Just scrolls, laser guns, and healing spells.

And gnomes?

 

[aramis erak]

Mystara: Poor Wizard’s Almanac I-III; Joshuan’s Almanac

Darak’s Thaumaturgical Printing Press (AC11, 28)

I knew there was a reason I didn't include Mystara - yeah, the Republic of Darrokin is fully renaissance save guns, and has presses in canon.

 

[Fenris-77]

My published setting for Shadowdark does have the printing press (and firearms). That said, I haven't explored the book aspect of the setting too deeply. My current project, a city supplement, is putting the printing press front and center however. Broadsheets sold on streetcorners by shouting young entrepreneurs and a new mania for book ownership and collecting both feature strongly. I have used rare books as treasure in many of my adventures as well, so this is building on that.

My setting is strongly WHFRP adjacent, so I didn't agonize about firearms or the printing press, I just jammed them in and pressed frappe.