What’s up 11w brethren?

I have made the decision (with support from my wife - which is a big motivator) to write a book. It is a specific topic, related to finance, but serves a large niche (yea that is kind of an oxymoron, but it’s true).

Don’t want to give too much away, but wanted to see if anyone has written a book or went through the process? I have created a table of contents, outlines my intro, and have the goals or outcomes established for what I would like the readers to take away from my writing.

i am going to be working on creating the intro, and I was thinking about sending the intro, and supporting documents to some publishers as a proof of concept to see if the idea has legs. I truly believe it does. The research I have done shows me that so many people struggle with the main premise of the book, but nothing is out there on the market (at least from what I could find) that addresses this.

so the question, would my thought process of sending a proof of concept be valid, or should I write more, maybe 25% or 50% and then introduce to publishers? Or at least try? Will publishers even take a Propf of concept in that way? Really in the nascent stages of this but I am VERY excited and motivated. 
 

any thoughts? Comments, feedback? Don’t want to give out too much so as to not jinx it, lol. But really any insight is appreciated.

love the community and love all you guys and gals. Thanks in advance.