Here you will find the collective experience of three writers and editors distilled into a complete guide to writing science fiction. Separate chapters cover Idea, Plot, Character, Background, Science, Tragedy, and Comedy. Twelve stories, each a first sale by its author, illustrate the main points of the book. A foreword by Isaac Asimov gives an overall look at the task of becoming an SF writer, and an appendix by the editors explains exactly how to prepare a manuscript for publication.
Some of this advice, particularly the parts about submitting manuscripts to magazines and other comments about the writer's market, are obviously outdated. But the writing advice itself is not only evergreen, most of it applies equally well to any genre of fiction. Definitely worth a read for any aspiring writer, especially since the authors are all accomplished editors with long and influential careers.
However, it's still a book of general writing advice. While each section has a story or three to show what the editors are discussing, it lacks the depth of a more specialized discussion. I don't think that lessens any of the advice given, but this book alone may not be enough for someone seeking deeper insights into a particular aspect of writing.
On Writing Science Fiction is about writing science fiction only as a topic, not as a focus. Somewhere in the book is a money-line about the book teaching writing first, fiction writing second and writing science fiction last. Quite true and accurate! This book is a gem for anyone who wants to write. Don't worry about the genre aspect, it's a great study. (you can read the rest of my review on my blog)