Enchanted Glass by Diana Wynne Jones

I just read this book - written for the age11-15 range and I really enjoyed it!  I looked up the author online and was very sad to learn that she recently passed away.  Here is her website: http://www.leemac.freeserve.co.uk/
This book is about two people - Andrew Hope, who inherited Melstone house when his uncle died and a young, recently orphaned boy named Aiden Cain who showed up at his door one day looking for Andrew's grandfather. Andrew's grandfather - and Aiden's grandmother had both been magicians of a sort with field's of care and Andrew, with help from Aiden,  must remember the magic that he learned from his grandfather when he was a boy to reclaim his field of care from the devious Mr. Brown.
I enjoyed this book and now want to read some of Ms. Jones's other books.