The Original Series Reading List lacks a main ongoing storyline that is the hallmark of the other series' literary continuities. However, some prominent storylines and tales can be picked out. The majority of The Original Series novels are stand-alone, and most can easily be read in any order. Accordingly there are no obvious "jumping on points" which the other series can be said to have.

Many The Original Series stories in the last two decades have included elements of the wider Lit-verse, so many novels, short stories, comics, and audiobooks are connected due to various references in other books, or to other books. These references are mentioned in the notes.

Other novels are connected by five crossover series: Invasion! (which is referenced several times in the Lit-verse), Day of Honor (which shares references with several things in the Lit-verse), The Captain's Table (which is thematically connected to the Lit-verse spanning Tales From the Captain's Table), Section 31 (which ties into the Deep Space Nine Post-Finale Series,) and Gateways (which ties into the Deep Space Nine Post-Finale Series and the New Frontier series.)

Nine other short stories or novellas are also connected: five from Enterprise Logs (which shares references among several connected novels), two from Deep Space Nine: The Lives of Dax (which ties into the Deep Space Nine Post-Finale Series), one from The Brave and the Bold duology (which ties into the Gorkon series), and one from Seven Deadly Sins (which ties into three Lit-verse series.)

Five novels and one ebook in other series cross over with The Original Series: Discovery: Drastic Measures, Discovery: Desperate Hours, Department of Temporal Investigations: Forgotten History, Vanguard: Harbinger, Vanguard: Storming Heaven, and Vanguard: In Tempest's Wake.

Also included are the stories from Constellations (one story of which is referenced in The Next Generation: Before Dishonor), and Mere Anarchy (which references several other stories.) Various references in parts of the Crew series, New Visions: Issue #5, Peter Pan Record #1, the Year Five series, the Wildstorm Star Trek Special, Star Trek #400, and the DC Volume 2 Special #2 connect The Original Series stories from those works. 

The Original Series Reading List stops at the disappearance of James T. Kirk aboard the Enterprise-B and all storylines transfer to "The Lost Era", the Early 24th Century Reading List.

In addition there are the novels that comprised the "Original Lit-verse" of the 1980s. This was a group of stories which were eventually linked together through references and shared characters. Of particular importance to the later Lit-verse are the original two Rihannsu novels, The Final Reflection, and the novelizations of The Motion Picture and The Wrath of Khan, many elements of which have been more or less incorporated into the modern continuity, though undoubtedly requiring a certain amount of retconning.

The earliest book eventually connected to the "Original Lit-verse" was published in 1977. The continuity flourished throughout the 1980s under editor Dave Stern. Around 1988, under the direction of Gene Roddenberry and Richard Arnold, a push was made to cut back on shared characters and references between novels. This was not a hard rule, and references between books and between comics continued at a slower pace through the mid 1990s under Stern and Kevin Ryan. I place the end of this era, and the advent of the modern Lit-verse, around 1995/1996, under editor John Ordover.

Closely connected to these books was the DC Comics series of the 1980s. Characters were sometimes shared between the two series. Several "Original Lit-verse" novels have been referenced in the modern continuity, more or less linking both bodies of work, though of course with continuity difficulties. The numbering system of the "Original Lit-verse" included here is strictly chronological and did not originate from the authors' or editors' intent. 

(Note that an explanation for my order of episodes and novels during the Five Year Mission can be seen here: The Five Year Mission: Month-By-Month. This is a very specific order that does not always match production order or airdate.)

(Note that the covers of many The Original Series books contain Enterprise designs or Starfleet uniforms which do not match the era of the book, and which sometimes do not even match each other. These should be disregarded.)

Dark blue denotes the works most closely linked to the Lit-verse. Read any or all of these to expand on The Original Series era from the Lit-verse's perspective. Light blue denotes the more expanded storyline. Read these for other works closely connected to the Lit-verse. Dark green denotes the Original Lit-verse. Light green denotes the DC Comics continuity, which was interconnected with the Original Lit-verse novels. Many stories cross between two or more of these categories, and the categories themselves, in the case of The Original Series, could be flexible. The white denotes every other connected story, regardless of continuity. 

Hover for notes. As always, not every reference to every other story is mentioned, just the one I chose as most important to show the expanding Lit-verse web.