I loved this! Such a cool idea. It only covers the first two books in the series, but for each book you are given a calendar with chapters to read to let you read events “as they happened” on the exact dates of the year. Then Ms. Harkness gives you her inspirations for people, places, things, and music that goes with things in the stories. It really is a companion to use as you read, however, I didn’t get it until I finished the second book, so now I’ll need to go back and re-read them together later. Even so, I enjoyed clicking the links to the YouTube videos for the songs she was thinking of for certain scenes or people, and the photos of the castles, clothes, books, and other things were wonderful! (Unfortunately some of the links don't work, but you can pretty easily google the info she gives to find the missing stuff.)
I highly recommend this if you enjoyed the first two books, especially since it's available free as a Kindle book on Amazon. I just wish there was another one to go with books 3 and 4. Hopefully someday she’ll write one. (Finished 9/16)