Office chairs, back chairs and untraditional relaxing chairs
There are many good models and brands of office chairs and companies that are supplying them; the following are some of these.
 

www.thebackshop.co.uk 14 New Cavendish St. London W1M 7LJ   020 7935 9120   catalogue available also more traditional armchairs, seating improvements

chairs for musicians, all legs adjustable
www.blackcatmusic.co.uk 01892 619719

www.postureeducation.com   ergonomic seat supports
order from Advance Seating

Interesting web sites

If you have back pain

If you want to learn how to sit

Home by Witold Rybczynski Pocket Books 2001
ISBN 0-7434-0443-2