"SF: The Challenge to the Writer" from Reginald Bretnor is a nuts and bolts look at sf writing skills including knowledge of science, science fiction literature, and mainstream literature. He gives a specific reading list.

"Star-flights and Fantasies: Sagas Still to Come" by Poul Anderson is interesting as a look at what makes a successful, large scale science fiction saga by looking at some specfic works, and he covers how he uses these prinicples when he wrote Tau Zero.

Hal Clement's "Hard Science and Touch Technology" looks at the different ways science can be used in a plot.

Using Scientology as an example, Norman Spinrad's "Rubber Sciences" looks at how to develop credible sounding imaginary technologies and sciences.

"Extrapolations and Quantum Jumps" from Alan E. Nourse looks at the basics of conflict, character, and theme and also how extrapolative principles can be used on each.

Theodore Sturgeon's "Future Writers in a Future World" is not useful for writing advice but interesting for what it says of Sturgeon's personal and artistic values.

Jerry Pournelle's "The Construction of Believable Societies" suggests writers ask questions about the nature of the relations between the sexes, the nature of family units and government and the effect of technology when building plausible future human societies.

"Men on Other Planets" by Frank Herbert is kind of annoying in its use of irrelevant material, but he does talk of the value of writing science fiction that assaults the reader's and author's assumptions about race and culture.

Katherine MacLean's "Alien Minds and Nonhuman Intelligences" is rather opaque and silly but does have some good points on the influence of environment on morality and conflict between species.

James Gunn's "Heroes, Heroines, Villains: The Characters in Science Fiction" looks at the common character types of science fiction.

"The Words in Science Fiction" is Larry Niven advice on coining new words for stories -- including the origin of his "corpsicle".

Jack Williamson's "Short Stories and Novelette" is nut-and-bolts advice on how to maintain suspense and thematic unity at different lengths of story.

John Brunner turns in a very useful look at writing novels in "The Science Fiction Novel".

"With the Eyes of a Demon: Seeing the Fantastic as a Video Image" is the inimitable Harlan Ellison's advice on screenwriting.

"The Science Fiction Professional" by Frederik Pohl is a look at getting an agent, lecturing, and publicity. Obviously, in the age of the Internet and social media, this has probably aged the most.

Despite a lot of essays from authors now obscure, an overall good book of advice on science fiction writing -- at least so it seems to me. However, since I've never published fiction, that's a theoretical perspective. ( )