How do I stop races from stealing my technology?

Short answer is you can't.

Longer is "you can't no matter what you try".

You could try not researching any tech

I don't think they can steal techs unless they take a planet.
I have never noticed them getting that much stronger even if I have much more advanced techs than they have.

And there is only one race with an espionage bonus (50%), all the others are set at 0.
And that race, the Drath Legion, never is all that strong from what I have seen.

I have never noticed them getting that much stronger even if I have much more advanced techs than they have.

I'm lucky if I steal two techs in a game other than by invading, despite having advanced espionage on 9 other civs from very early on. So whilst they probably CAN steal techs, it's not going to make much difference unless they get EXTREMELY lucky and happen to pinch your best weapon tech. This is even assuming the AI puts as much effort into espionage as me...I doubt they do.

And there is only one race with an espionage bonus (50%), all the others are set at 0. And that race, the Drath Legion, never is all that strong from what I have seen.

As well as the point I made above, I think the espionage bonus just reduces the amount of cash you have to spend to reach advanced. It doesn't make it more effective.

Does the game even tell you they stole a tech? Or do you have to keep checking the other races?

It never says they stole a tech, that would be against the whole point of espionage. And yes, the AI can and will steal tech from you through espionage. No, you can't stop it either. And the drath pwn you all.

Does the game even tell you they stole a tech? Or do you have to keep checking the other races?

After you complete a game it tells you how many techs each race stole on the tech score sheet.

Is it possible for me to steal techs my raise my espoinage?

You increase your espionage spending and once you are at a high level you will start automatically stealing techs. The freqency and quality of the techs depend on the other race's level and the difficulty of the game.

Espionage must be advanced, and does not require any spending once advanced has been reached.

It also virtually never happens. I play as Drath, who have the highest Espionage, and I count myself supremely lucky if I get more than one tech in a game, if that.

...

Okay, I swear this JUST hit me, but... could my failure to steal techs be caused by the fact that I already have all the techs (and more) that those races have? Haha, oops. Go Neutral!

So I am going to STEAL a tech from an ALIEN race ...

How HARD might this be ....

Even IF - I have trade, warm relay and No military threat ...
Watt about ... cultural diffs, language translates and watt-ever...
HOW DO YOU STEAL a Tech ?????
I am VERY LUCKY - if I ever, and I mean EVER ...
steal a tech ....
I find this part of GalCiv2 - to be very realistic !!!!!

AS for the so called " Minor Races" ...

SPY on them????

If they have ANYTHING I wont ....

I INVADE and OWN them ... post haste ...

Why are they MINOR anyway ...

CAUSE THEY DO NOT MATTER !!!!

that is why they are minor they don't matter, they don't grow and if you take over everyone else beside them you still win they don't make a different other then been there

I really hope Stardock lets me defend against tech stealing in the next patch.

Also, I am still experiencing a bug where I can't start new threads. It is detailed here. I hope stardock fixes this. I use Firefox, but the forum does not load on MSIE at all and on Netscape it loads but freezes Netscape.
https://www.galciv.wikia.com/wiki/User:SleepAtWork/forumbug

This is one of the areas of the game that could use some more depth, again I don't wanna go down the MOO route, but you can't fault excellence, obviously there should be a chance on each roll to...

stop a steal and spy gets caught point finger at originating empire (best case)
stop a steal and spy gets caught points finger at wrong empire
stop a steal but spy gets away
dont stop steal byt spy gets caught points finger at wrong empire
dont stop steal spy gets away but you find out about it
dont even know a steal occurs spy gets away clean
dont even know a steal occurs and spy gets away clean, spy's empire is so happy about it, they share the stolden tech with all its allies ( haha worst case pull your pants up and spend some CIA funds for crying out loud!)

Something like this, based on a percentage scale, D100 rolls, with an internal security modifier would be great, you could even have a variable modifier of internal security for each race like you have an espionage modifier right now.

Right now the game just looks like they were thinking about it but scrapped the idea because they wanted to make a release date and didn't really have the time or money to develop it fully. Not saying what is in the game doesn't work it's just that it isn't really all that deep or fun the way it is now. Another thing about it is it's pure espionage and there is no way to covertly create sabotage and screw with another empire below the belt. Come on that should be sooo much fun.

In MOO2 spying was like crime, eventually you got caught. Sabotague also did so little it didn't matter

I played MOO3 with all its spies and they were just really pesky and irritating. More deadly, yes, too.

But for GalCiv2, all I ask is for a way to stop them from stealing tech, and if isn't in the game a way to turn this off--even by a mod (although I'd prefer not to have to use a mod).