I happened to come across the recent (2006) book "Sun, Earth and Sky" (second edition) by Kenneth R. Lang in the local library. It has a wealth of information on all the most recent discoveries and is very well illustrated. Don't be fooled by the "Earth and Sky" parts of the title, this book is all about the Sun.

Not the most inexpensive book (e.g. via Amazon) but I thought it was a highly readable and fascinating book. Well worth checking to see if your local library has it.

Airbag