It is the "bible for digital nomads". Nice book, in the end you see he works more than 4 hours a week, but it is a catchy title.
I also wanted to travel around the world and that is also a reason i started online 15 years ago. So it is nothing new, but now more and more people get aware of the possibilities. The last year there are more and more people try to travel and make money online and it got attention of the biggest mainstream media. There are a lot of things, digital nomad cruises, co-work centers around the world, meet ups around the world, big events where thousands attend etcetra.
A lot of companies also hire digital nomads, or even relocate to the places where a lot of digital nomads hang-out like Chiang Mai, Bangkok, Vietnam and also Colombia is popular.
I travel around now for 5 years in several countries. Most of the time i stay 1 - 6 months in a country. Didn't need a book to know i wanted that. Most of the tie i was backpacking on my holidays. You see people now to pay to follow a course how to make money online in some nice places. I prefer the opposite, better to first learn and already make money online and than travel.
Why did you stay in your country for those 3 years? Here you can find some countries to stay with the cost
https://nomadlist.com The prices are an indication, some travel cheap, other only for 1 year and spent there savings. Most people i know spent around 600 - 800 euros a month.