Sometimes people like to compare books in series and focus on the one they like best, for me I like to look at each book on its own. It can help me be interested in a book if it is by an author I like, but some authors I love have written a book or two I don't like at all. I read Gather Blue, because it was a gift (from one of my dad's students), a recommendation and from an author I love, boy am I glad I did. I loved reading about Kira's futuristic world that could possibly existed at the same time as the world of Jonas (from the Giver). Gathering Blue worked really well as a companion to The Giver (SPOILER ALERT) and I liked how at the end there was a mention of a boy that could possibly be Jonas at the end (in the author interview in the back of my copy Lois Lowry noted that "there is a reference to a boy with light eyes at the end of Gathering Blue. He can be Jonas or not, as you wish."). Like The Giver this is a book that makes you think on many levels, I recommend it to older elementary and middle school readers and I really think you should read The Giver first.