A really easy-to-read book (Grace has a great, succinct writing style) with heaps of practical ideas to put into practice straightaway. You'll save the hour or two it takes to read it in the first day!
This book is fantastic for experienced writers as well as those just starting out. For experienced writers it's a handy reminder of the rules you should be following. For beginners it's a clear, step-by-step guide on how to get started. Easy to read, easy to refer back to it's one to keep on your desk and keep dipping into.