The Violet KeystoneThe Violet Keystone is the sixth and last book in Garth Nix's The Seventh Tower series, published in 2001 by Scholastic.The cover design and art are by Joan Moloney and Steve Rawlings respectively.SynopsisTal and Milla, along with some allies, are now face to face with the evil that plans to destroy their world. In this book, they travel one last time to Aenir, release their bonded Spiritshadows, and confront the mighty dragon Characters from [The Seventh Tower#Sharrakor|Sharrakor].Publication historyAfter the novel's initial publication by Scholastic it was reprinted by HarperCollins in 2010 and then translated into German in 2002, Portuguese and Czech in 2003, and Swedish in 2005.