Pound for pound, this may be the best book on, about, or for aspiring writers.
I have read at least 10 books on the craft of writing and a bunch on theory and technique... this book is right up there with the best of the best. If you couple this book with Raymond Carver's posthumous "Call if You Need Me" and mix in a few careful readings of any Richard Yates interview, you've got yourself some tough rope to tow. But if you want to be a strong writer, suck it up and do it anyway!
I hold a BA in fiction writing. I also tend to write literary realist fiction. If you are of the same mind, this book will help you tremendously. It is brutal in it's explanation of what to steer clear of and what to include, but that is how it should be. If you take writing very seriously, and want to take it to the next level, this book is a great start.
You can't go wrong when you have advice from C. Michael Curtis (Fiction Editor of the most prominent publication in America) and Frank Conroy (Chairman to the most prestegious writing institute in America.) Pay attention folks. This is the real deal. Add in some very helpful workshop activites from one Tom Bailey (only a head writing professor at Harvard) and some very heartfelt tips from a true master like Dubus... Forget about it!
"On becoming a Novelist" was good. "ABCs of Reading" was good. "The Lonely Voice" was decent. Forster's guidance was revolutionary, but this book is perfect for now. Go buy it and then read all the Carver and Yates and Dubus and Wolff you can get your grubby little hands on. You'll be a better writer for it. Trust me!