> ebook in a niche technical topic It won't get you much passive income, if the topic is very niche. If it is more popular, there's bigger competition, so you

> ebook in a niche technical topic It won't get you much passive income, if the topic is very niche. If it is more popular, there's bigger competition, so you have to be lucky. I wrote a technical book (ebook + paperback) in veeery niche technical topic (and it's the only book on this topic on the market), got one-time moderate paycheck from the publisher and that was it. If the book gets me any passive income it will be just a few buck a month, not earlier than in 2-3 years (when the book will be obsolete anyway...) What I earned was invaluable experience and some insight into how I work and how I can improve it, but that's it.