I've often wanted to manipulate the AI's choice in what Tech to research next, and (plainly) "Flavors" don't do the trick. A simple example which I'm working with in Terra Fantasia is to "lure" each of the four equivalents of flavors down certain paths. Anyone here who's done some modding (is there anyone who hasn't?) has already - partially correctly - surmised that this involves using Techs not required for Era advancement. What I've worked out covers both that method, as well as forcing certain Civs to research certain Techs in a specific order. To be clear, this is probably most useful when a Tech tree branches (let's keep it simple, for explanation) into a choice of 2 different Techs, with each of those leading to another, single Tech. You'll also see how this can be used in more complex fashions, but here are the basics. Long ago, a fellow called Alexman derived the point value which the AI assigns to each attribute for a Tech, and then goes with the highest number. Here's the list: SS Component: 261/turns Government: 259/turns Conscription: 259/turns Mobilization: 259/turns Defender (no resource): 198 Attacker (no resource): 134 No trade: 149/turns Defender (resource reqd): 70 Naval Transport: 34 Resource (lux, strat, bonus): 16 Double Worker Speed: 8 Allows Diplomats: 8 MPPs: 8 ROPs: 8 Alliances: 8 Embargoes: 8 Trade Over Ocean: 8 Attacker (resource reqd): 6 Wonder: 6 Irrigation: 4 No Disease: 4 Trade Over Sea: 4 Bridges: 2 Double Wealth: 2 Map Trades: 2 Communications Trade: 2 Small Wonder: 2 Specialist: 2 Unit (no A/D/NT): 2 Improvement: 2 Other tech: 1 Recycling: 1 Prec. Bombing: 1 Worker Job: 1 Bonus Tech: 0 Reveal Map: 0 Sacrifices: 0 Empty Tech Cost: 256/turns Optional: divide by 1.5 - And, no, I have no idea at all, what the last "Optional" point means. Aside from getting getting into complex math with small numbers, two significant methods jump out: Give the Civ a Defender unit, which requires a resource, and which only it can build - 70 Points. Make up a Resource - "Unobtaineum" - and stick it someplace on the map which is utterly inaccessible. Enable the "Space Race" victory condition - and make certain that there's one, or more, less parts available than to actually be able to build the ship. (As the Player would never build any of those parts, the game would never be interrupted by any spaceship building graphics.) Yes, this gives the Player an obvious advantage, but it can be quite minor, especially if, e.g., those Space Ship parts cost (again, for example's sake) 10 build points. Plainly, there are many other possible options here, but I'm hoping that this is a good start.