Investing in a New Segment of the Market?

If i am wishing to invest in a new segment of the market that i am currently not familiar with, how much knowledge of the industry would you deem appropriate before feeling confident enough to invest in it? Are interested to hear your thoughts. Yes, this is a good question, really good question. Ah, look, there's the whole concept of analysis paralysis. And for me, personally, i would not feel comfortable getting into a new business in a new industry until i've really read up on that business and also the other main players in that industry. Let truth be told, that wouldn't be a fast process. That being said, i think it's important never to rush in the market...