A UK based charity run by unpaid volunteers, many of whom will be fibromyalgia sufferers themselves. Seeks to “improve the lives of people with fibromyalgia by increasing awareness of the condition throughout the UK and elsewhere, and improve the awareness of, and access to treatments for fibromyalgia.”
Formerly Arthritis Research UK has a lot of useful information about fibromyalgia
Authored by Dr Daniel Clauw, a Rheumatologist and Prof of Anaesthesiology and Medicine at the Chronic Pain & Fatigue Research Centre, University of Michigan. Although this guide may seem little dated (2014) it is one of the most useful and comprehensive guides to understanding and living with fibromyalgia that I have come across. This may not be accessible on mobile devices.