The term "in-universe" refers to information presented in the context of the Star Wars universe itself, as opposed to "out-of-universe," information presented in the context of the real world. For instance, the in-universe reason that Han Solo has a scar on his chin is that it was the result of a fight with a knife-wielding thug on Dellalt, while the out-of-universe reason he has it is that the actor who portrayed him, Harrison Ford, has a scar on his chin from a car accident.
"In-universe" also refers to works presented as if they were written by authors within the Star Wars universe. In-universe works are often general-readership source material like The Essential Guide to Alien Species or roleplaying game books like The Thrawn Trilogy Sourcebook and Platt's Smugglers Guide. To maintain the conceit that they come from within the Star Wars universe, such works omit mention of Star Wars as films or as a media franchise, maintain ignorance of information from later in the timeline than the books are allegedly written, and often posit a fictional "author" to be the in-universe creator of the work in question.
- Ebenn Q3 Baobab (Galactic Phrase Book & Travel Guide)
- Airen Cracken (Cracken's Rebel Field Guide, Cracken's Rebel Operatives)
- Dossier for Airen Cracken (Cracken's Threat Dossier)
- Tem Eliss (Galaxy Guide 12: Aliens — Enemies and Allies)
- Arhul Hextrophon (The Rebel Alliance Sourcebook, Imperial Sourcebook)
- Mammon Hoole (The Essential Guide to Alien Species)
- Voren Na'al (Galaxy Guide 1: A New Hope, Galaxy Guide 3: The Empire Strikes Back, Galaxy Guide 5: Return of the Jedi, The New Essential Chronology)
- Platt Okeefe (Smuggler's Log, Platt's Smugglers Guide, Platt's Starport Guide)
- Obo Rin (Galaxy Guide 4: Alien Races)
- Tionne Solusar (Jedi vs. Sith: The Essential Guide to the Force)
- Lyrre T'enna (The Wildlife of Star Wars: A Field Guide) (Primary researcher)
- Milanda Vorgan (The Written Word)
- Darth Sidious (Book of Sith) (Compiler and co-author)