I publish just 4-6 books per year as a one-man show, and most of those books begin as a referral of one writer by another, or as a conversation that begins well and continues. Because my capacity for reading manuscripts is limited, it's best to send me a query describing your work, as briefly and artfully as possible, and use that to open a conversation. I'll be as responsive as I can and as the quality of query demands. If I'm impressed with your approach, I'll ask you to send a manuscript. Conversations lead to books when the work merits, when I think I can market the work successfully, and when the conversation gets us there.
So please don't send a manuscript before it's requested. Begin with a query. Thanks...