So we're thinking of playing the Serenity RPG. It seems that the main rulebook is Big Damn Heroes. Do we need any other books to get started? In particular, do we require something like the Cortex Role Playing Game System? Are there any other books/accessories that would be absolutely necessary to play?
[RPG] Required set of books for Serenity RPG
booksserenity
Related Solutions
The basic three books -- Player's Handbook, Dungeon Master's Guide, and Monster Manual -- will give you what you need. You can find hard copies if you look online, possibly as a gift set. If you're experienced with other editions, you'll notice the lack of barbarian, bard, druid, half-orc and gnome options; those were included in Player's Handbook 2, and psionic classes of note, particularly the monk, were the focus of Player's Handbook 3.
Be aware that there are a fair number of rules updates that affect these. You can find the full list here.
For the Essentials line here's the breakdown of what I think you'll want if you go in that direction: the Dungeons & Dragons Fantasy Roleplaying Game Starter Set, as an optional tutorial; the Dungeon Master's Kit, which is the equivalent of the Dungeon Master's Guide; the Monster Vault; and one or both of Heroes of the Fallen Lands and Heroes of the Forgotten Kingdoms, which give player options. The first three of those were boxed sets, and you'd wind up with three or four adventures, some dungeon terrain tiles, a ton of tokens to use instead of miniatures, and a DM screen; these things are not included with the digital releases, however, so you might need to turn to external resellers. You may also want the Rules Compendium -- it has some rules not covered by the DM's Kit, but is more of value to people who have the core books and don't want to look up errata to rules.
The advantage of Essentials is that it's an easier entrance point, particularly if you're familiar with an older edition. Also, it doesn't have a ton of errata.
If you buy either group of books and later want to use material from the other group, that should be possible without any fuss.
Finally, I'll agree that the Dungeons & Dragons Insider subscription is a good purchase. You did get (in 2010) access to an online database containing every rules option from every source; you get a character builder, which also has all the options (Windows and Mac only); and you get daily articles. (2021 update: subscribing to DDI is no longer possible and the content needs to be picked up piecemeal. Dragon magazine is still available)
Many of the Classic Traveller adventure materials could be easily adapted.
easily adaptable:
Adv 8 Prison Planet
Adv 9 Nomads of the World Ocean
Adv 11 Murder on Arcturus Station
Most of Sup 6 76 patrons
CT D02 Double 02a Across The Bright Face/Mission On Mithril - both halves!
CT D04 Double 04a Marooned/Marooned Alone
Some "rather iffy - bends the 'verse" Traveller adventures:
Adv 2: Research Station Gamma - intelligent aliens; otherwise, a rather doable conversion
Adv 7: Broadsword - the adventure itself is suitable, but most of the module isn't the adventure.
Adv 10 Safari Ship - again, more about the ship than the adventure
CT D01 01a Annic Nova/Shadows - both deal with aliens pre-current imperium.
CT D05 Double 05a The Chamax Plague/Horde - Alien life.
Ones that don't fit well
Adv 1: Kinunir - it's a "show off the system mechanics" issue.
Adv 3: Twilight's Peak - intelligent aliens; ancients. Strongly OTU
Adv 4: Leviathan - another "show off the mechanics"
Adv 5: Trillion Credit Squadron - Not an adventure
Adv 6: Expedition to Zhodane - Aliens, specific-to-OTU theme.
Adv 12 Secret of the Ancients- Aliens, specific-to-OTU theme.
Adv 13 Signal GK- Aliens, specific-to-OTU theme.
The Traveller Adventure is chock full of useful stuff, but the campaign metaplot is unusable due to both being too OTU, and involving too many aliens. Many chapters, however, are perfect fits... Zilan Wine comes to mind immediately.
MT didn't have many separately published, tho' many were in Traveller's Digest or in Challenge. Both Knightfall and The Flaming Eye are so OTU focused that conversions would be unrecogniable and lots of work.
Mongoose's Traveller has a few that could be easily adapted... In general, tho' only 760 Patrons really is worth the time.
Best Answer
The Serenity Role Playing Game book is a complete game in and of itself. It's the "core rules" for the Serenity game.
You don't need the Cortex System book, and in fact, due to differences between the two, it's only going to confuse things.
You probably should get the Big Damn Heroes Handbook. The rules and setting expansion it provides is worth the money. Hell, the extra 'verse chinese is almost worth it...
You need:
It really helps to have:
The line, as best I can tell:
Core rules. Note that this is a stand alone game including all the cortex system rules you need
Rules upgrades and additional setting material
Additional gear and ships, plus more sample crews
Long adventure/short campaign.
5 short adventures
Just the screen and a poster-map of deckplans.
And it looks like the line's been canceled, by the way. It's no longer available in PDF from Drive Thru, nor mentioned on MargaretWeis.com online store. (and it was available in PDF in april 2011.)
There is a good bit of fan-written material, as well, mostly ships and adventures.
As a bit of an aside:
The first Cortex System game was Larry Elmore's Sovereign Stone.
The second Cortex System game was the Serenity RPG.
Both predate the Cortex System being named such; both stand alone, and both differ from the later Cortex System Core Rules in a number of small ways, but only in small ways.