I am a developer and I just wrote my first book. It's a computer book about a database called Postgres. The book is called "Essential Postgres: Database Development using PostgreSQL".
The book just appeared on Amazon for the first time today. The eBook won't be available for another week or so.
I have no idea if the book will sell 3 copies or 3,000 copies. It'll be interesting to find out. Wish me luck.