There is more to becoming a successful writer than mastering the rules of grammar and syntax and being gifted with the ability to put to paper an interesting string of words.
As with some other books on the business of writing, I did not realize the value of the book when I bought it long ago. Man, was I an arrogant shmegege. So, I have happily begun to re-read it.
I don't know if it is still in print, but if you write for some portion of your living, especially if you freelance, and you see a copy, you should buy it.
Enjoy the way the book is broken down into 75 small steps, some of which you can simply gloss over if it does not pertain to the writing you do. Can usualy find it in the bargain section of Barnes & Noble.