If a book you have written is accepted by an editor, more often than not you will get what is known in the trade as an “Editorial letter.” I doubt very much if anyone has formulated how these letters should be composed, but over the years, considering the many such letters I have received, they follow an almost standardized form.
Aside from a kind welcoming greeting, and a restatement that the editor is pleased to be publishing your book, the letter will start by reviewing the positive aspects of what you have written. This is gratifying, because it suggests you have been successful in vital ways. After all, your book has been accepted for publication. There is nothing wrong with accepting the praise. Indeed, it is important you do, because of what comes next.
Because what comes next is an outline of your book’s weakness, and ways it can be improved.
These points and how they are presented—are the key to the writer/editor relationship. Even when these points are offered as “suggestions,” they are often more than that, which is to say you must give these ideas your absolute attention.
Yes, it is the editor’s responsibility to understand what you have tried to do, and there is an equal responsibility to present these suggestions in clear, understandable fashion. (An editor once said to me “Just rewrite the book.” Not helpful.) Nevertheless, you must accept the basic premise of the editor’s letter that she/he is trying to help you write a better book.
My own approach is always to try to do what the editor suggests. My experience is that most times, they are right, and you will get a better book when you implement these ideas.
When in doubt reread the letter’s first paragraph—enjoy it—and then get on with the work of revisions.