Found in 6 comments
sebkap · 2018-03-06 · Original thread
I recommend Gokhale method (https://www.amazon.com/Steps-Pain-Free-Back-Solutions-Should...) which helped me fix my back pain and allow to sit for long periods of time without any problem. This book will teach you how to sit correctly and few other things about your back.
msluyter · 2014-01-30 · Original thread
+1 on that book. It's by Esther Gokhale:

http://www.amazon.com/Steps-Pain-Free-Back-Solutions-Shoulde...

PS: Also learn good posture from a good yoga or martial arts instructor.

Read books like this: http://www.amazon.com/Steps-Pain-Free-Back-Solutions-Shoulde...

No, you don't need expensive chairs for coding, you don't need to "sit down well" because it is not possible or good for you. Do sit for hours in a "correct" posture and you will discover that your body tries to move constantly from it (blood circulation needs your pressure points to change constantly or bruises will appear).

Instead of buying expensive things go buy experts book on the area of posture, or better, go talk with expert people in the field. Books like this helped me in the past(I had pain in my back years ago) : http://www.amazon.com/Steps-Pain-Free-Back-Solutions-Shoulde...

But I assert you that in the area you live there is already lots of good people that could help you. In my area I found a martial arts expert(that won Olympic gold medals when young) that could identify wrong postures from an eye shot.

PS: I code mostly standing up and with a high stool.

udfalkso · 2010-10-04 · Original thread
This excellent book explains many of the same ideas.

http://www.amazon.com/Steps-Pain-Free-Back-Solutions-Shoulde...

staktrace · 2010-09-29 · Original thread
For those interested, there's a book on this topic that is excellent and provides 8 postures improvements (complete with pictures) that will help keep pain away. http://www.amazon.com/Steps-Pain-Free-Back-Solutions-Shoulde... - there's also an Authors@Google talk by the author on Youtube (http://www.youtube.com/watch?v=-yYJ4hEYudE) if you want a taste before buying the book.
View this Book on Amazon