Legend to Tech Tree:

(xxx) Research Point Cost - Number of Research Points needed to complete research of tech. 1/100 of this cost is used in the technology's upkeep.

(-x) Church Dislike Factor - The lower the number the more likely the chance the Church will proscribe that particular tech. If the bonus is -5 or lower, it is automatically proscribed at the beginning of the game.

-- Only prerequisite - Indicates that this tech has no other techs as a prerequisite.

++ Requires other techs - Indicates that this tech has other techs as a prerequisite.

... Tech tree continues - Indicates that further research down this tech tree is possible.

<> Unit tech only prerequisite - Indicates that the Applied (or Unit) Tech has no other techs as a prerequisite.

>< Unit tech requires other techs - Indicates that the Applied (or Unit) Tech has other techs as a prerequisite.

Build X(...) - Indicates that X is now available for building by an Engineer, Demolition Team, or Colony Ship. The ellipsis (...) indicates that structure X can build special units.

Build X in Y(...) - Indicates that X can now be built in structure Y. If the ellipsis (...) follows Y then X is an upgrade for a future unit.

Upgrade X to Z at Y(..., +++) - Indicates that X can now be upgraded to Z at structure Y. Also note that Z can be disbanded back to X. The ellipsis (...) indicates that unit Z is an upgrade for a future unit. The symbol, +++, indicates that unit X can be upgraded to another unit.

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In the Build section this indicates that all proceeding units require the current prerequisite technology as well as at least one other technology to be able to build these units.
