The latest is Jian 8. I recommend several books commonly used in IELTS test: Cambridge 4-8 (required test), which can be used to familiarize yourself with questions, practice repeatedly and conduct model tests. Wang Lu 807 listening vocabulary (required), IELTS reading high-frequency vocabulary (this can be included), IELTS reading real questions, 9-point reading (this book is a tutorial book that I have read in Cambridge for more than 4-8 2 times, but I still don't think I have read enough), Shen Xiaoya's breakthrough in oral English for 10 days, IELTS writing for 10 days, IELTS writing for 10 days, complete test bank, and black-eyed series listening (as the first contact with IELTS listening exercise book, do Cambridge again).