Harriet's books have helped me improve the accuracy of piecing. While I have thought about doing all the exercises in each of the 4 books, I haven't. However, I've read through them many times and when I have a specific technique to do -- half square triangles, etc. -- I follow her advice. The first time I was able to nest seams without having to pin sold me on doing it Harriet's way. I took a machine quilting class from her a few years ago, and she was fantastic and her quilts are outstanding. Her "Quilters Academy" Freshman thru Senior years are must have's. I think her 5th book is coming out this year. If you are a machine quilter, get her "Heirloom Machine Quilting." I also have her "Mastering Machine Applique." However, I prefer doing my applique by hand. Check out her website and store.