Forget the Star Trek spinoff series, all the Star Trek films, and every other space-SF series that has hit the airwaves since the original Star Trek was made. They're pikers, amateurs, also-rans. Babylon 5 is the true spiritual successor to the original Trek, the finest space-based science fiction to hit the small screen in at least the last thirty years.
Babylon 5 is a space station that orbits a planet light-years from nowhere, deep in neutral territory. It's a cross between what the United Nations was supposed to be and Casablanca, in space. Babylon 5 tells the story of this place, a grand sweeping epic that involves five years, three wars, and countless people from many different species in a far-reaching web of events that changes the course of history for the entire galaxy.
Naturally Babylon 5 spawned tie-in books, both fiction and nonfiction. The nonfiction books take the form of "Making of" type things and season-by-season episode guides:
Jane Killick wrote episode guides to each of the five seasons of Babylon 5. I have all five. Each includes a plot summary and discussion for each episode produced during that season. They don't cover everything, but what they do cover, they cover pretty well.
BABYLON 5: SIGNS AND PORTENTS deals with Season 1, in which only distant storm-clouds appear on the horizon while Babylon 5 is getting going.
BABYLON 5: THE COMING OF SHADOWS describes Season 2. While the Narn and Centauri go to war, the dark enemy known only as "the Shadows" begins to move behind the scenes, and Babylon 5 drifts toward troubles of its own.
BABYLON 5: POINT OF NO RETURN handles Season 3. Several crises erupt into interstellar war, and Babylon 5 finds itself at the heart of the storm.
BABYLON 5: NO SURRENDER, NO RETREAT talks about Season 4, in which the existing major story arcs are resolved (not always happily), and a few seeds are planted for the future.
BABYLON 5: THE WHEEL OF FIRE talks about Season 5. In the aftermath of the great wars, new problems arise and some old ones resurface, producing a whole new set of troubles for the crew of Babylon 5. This season deals with some loose ends from the previous ones, includes a couple of small arcs of its own, and generally wraps up the story of Babylon 5 pretty well.
I also have a couple of "behind the scenes" type of books about Babylon 5:
CREATING BABYLON 5 by David Bassom is a behind-the-scenes look at the production of the series, including interviews with cast and crew, descriptions of a typical day on the set, details on production and post-production, and so on. Very nicely done.
BABYLON 5 SECURITY MANUAL, by Jim Mortimore, is a sort of mockup of what a real B5 security guidebook might be like. It includes details on station procedures, alien races, ships, politics, weaponry, training, and so on. Accurate, informative, and fun.
In addition to the above books, Babylon 5 also spawned a series of spinoff novels. At first the publisher tried doing them like Star Trek novels: independent adventures set in the B5 universe using B5 characters. However, those novels came out truly wretched (in my opinion -- I've read three and didn't like any of them), so J. Michael Straczynski started exercising closer control over their content, making sure they fit the B5 universe. As a result, some of the more recent B5 novels have been as good as any SF I've read in quite a while, far above the usual Star Trek or Star Wars spinoff. These novels are carefully planned to fill in gaps in the B5 storyline, stuff that took place "off camera" or before or after the five-year period covered by the series run.
THE SHADOW WITHIN, by Jeanne Cavelos, tells the story of an ill-fated Earth explorer ship, the Icarus. The Icarus was sent on what the crew thought was a routine exploration of an uninhabited world, only to find out that it wasn't as deserted as they thought, and the inhabitants were not at all friendly. In the process, they became one of the major triggers of the Shadow War which dominated the series' third and fourth seasons. The story focuses on two characters who are already familiar from the TV series: Anna Sheridan, wife of Babylon 5's second commander, and Morden, who becomes one of the Shadows' chief agents.
TO DREAM IN THE CITY OF SORROWS, by Kathryn Drennan, is about the experiences of Jeffrey Sinclair after he left Babylon 5 (at the end of the first TV season) and traveled to the Minbari homeworld as the first Earth ambassador to Minbar. This book also tells the story of the Minbari Anla'shok, the Rangers, and how Sinclair became their leader and began building them into a force that could defeat their ancient enemies, the Shadows.
The PsiCorps Trilogy, by J. Gregory Keyes, is three independent but related novels that together tell major parts (not all, but parts) of the story of the PsiCorps, the organization that Earth set up to track and control human telepaths. These are very well-written books, with powerful characterizations and equally strong storytelling, which place them head and shoulders above 90% of the other spinoff novels I've read.
- DARK GENESIS: THE BIRTH OF THE PSI CORPS tells of how telepaths first appeared on Earth, how they were feared, hated, persecuted, and eventually formed into the PsiCorps for their own protection. It also fills in gaps in the history of telepaths, telling why they appeared when they did, and how and why the Telepath Resistance was formed.
- DEADLY RELATIONS: BESTER ASCENDANT describes the childhood and youth of Alfred Bester, a powerful telepath and Psi Cop who eventually rose to be a true power in the PsiCorps. Bester's appearances on Babylon 5 all fall in the years immediately after this book ends.
- FINAL RECKONING: THE FATE OF BESTER is exactly what the title says: Bester's ultimate fate after the Telepath War, some ten to fifteen years after the end of the TV series.
A second trilogy is Legions of Fire, by veteran SF writer Peter David. These three novels about Londo Mollari and events in the Centauri Republic after the events of Babylon 5's fifth season. Late in fifth season, Centauri Prime was taken over by agents of the defeated Shadows. This trilogy tells the history of Centauri Prime after that takeover, and what happened to the planet and its Emperor.
- THE LONG NIGHT OF CENTAURI PRIME, first in the Centauri trilogy, tells of the Drakh takeover of Centauri Prime and of its newly crowned Emperor Londo Mollari. A very good piece of work, far better than any of David's Star Trek novels. David does a very good job of showing Londo's anguish as he is forced to become a tool of the Drakh, and cut himself off from every friend he has.
- ARMIES OF LIGHT AND DARK describes the next few years on Centauri Prime. Londo Mollari is a passive Emperor, lost in his own thoughts and self-loathing. An ambitious, arrogant, conceited underling becomes the Drakh's primary tool in rebuilding the Centauri Republic into their tool of vengeance. Vir Cotto becomes leader of a Centauri Resistance movement against the government -- and the Drakh, although they don't know it. Vir also plays a critical role in events leading up to the Drakh attack on Earth (shown in the B5 made-for-TV movie BABYLON 5: A CALL TO ARMS.
- OUT OF THE DARKNESS describes the end of Londo's reign and of the Drakh presence on Centauri Prime. It finishes the job of connecting events between Season 5 of BABYLON 5 and the 'flashforward' that Sheridan saw of Centauri Prime seventeen years in the future.
The last B5 novels that I bought were the Technomage trilogy, The Passing of the Techno-Mages, by SF writer and editor Jeanne Cavelos. The Technomages are among the most interesting of Babylon 5's creations: an assemblage of beings from many intelligent species who share two things: a thirst for knowledge and a set of biological and cybernetic implants which give them a limited ability to control matter and energy. In short, they can use advanced nano-technology to produce effects that most people would call magic, thus "technomages." The Technomage trilogy delves deep into the background of the Technomages, explaining how they came to be and how they tie into the Babylon 5 universe and storylines. The trilogy timeline corresponds roughly to seasons 2 and 3 of the TV series, and shows many of the same events from very different perspectives.
- CASTING SHADOWS focuses on Galen, an apprentice Technomage who is about to be promoted to full mage status. Galen has a problem: he understands his mage-technology but can't fully control it, for reasons no one understands. But he will have to learn control soon and swiftly, because the Shadows are beginning to move, and the Technomages are one of their first targets.
- In SUMMONING LIGHT, the Technomages' Ruling Circle decides that the mages will flee and hide rather than joining the Shadow War on either side. But Galen does not want to run. He wants to fight, to use his powers to defeat the enemy Shadows and also to gain revenge on the evil technomage Elizar who serves the Shadows and killed Galen's lover Isabelle. But when he sets out to do so, he discovers the secrets behind the mage-technology -- secrets that the Circle knew all along, and hid from the rest of the mages, secrets that could destroy them all.
- The final book in the trilogy is INVOKING DARKNESS. The Order of the technomages is disintegrating, as the secret commands implanted within their technology twist their minds and set them against each other. Still seeking revenge, Galen wins permission to leave the Technomages' hiding place and aid in the war against the Shadows. His pursuit leads him to the Shadows' homeworld of Z'ha'dum, an unintended meeting with John Sheridan, and the greatest technomage secret of all.
I also have a Babylon 5 CD-ROM, THE OFFICIAL GUIDE TO BABYLON 5, which is a guide to the space station, different races, ships, and weapons of the Babylon 5 universe.