Self-pub or trad pub, it doesn’t matter. Everyone needs a query letter.
“Not me,” some will say. “I’m my own boss and CreateSpace doesn’t reject anyone! I don’t need your Big 5 (4… 3… 2…) Hegemony!”
Okay, cool. But what are you going to write for your book’s backmatter? What do you want to put on your cover? What do you say when you meet Adam Savage in an elevator and he asks you what your book is about?
The query letter is the mission statement of a book. You have to take it seriously, whether you’re sending it to agents or self-marketing. It’ll inform you about your differentiators, help set the visual tone and create a strong sense of your identity as an author.
You’ll need every part of a query to market your self-pub. Paragraph 1 contains your log line, paragraph 2 contains your synopsis and paragraph 3 contains your bio. You already have to write it, so why not start out right?