Ernest Hemingway on Writing is an extremely useful and interesting book. I wouldn't encourage my students to accept Hemingway's advice uncritically but I would certainly want them to read it.
There are problems with taking passages out of context but, nonetheless, Larry Phillips has done us a service by publishing many of Hemingway's comments about the business of writing in one volume. Take these words, for example:
"Actually if a writer needs a dictionary he should not write. He should have read the dictionary at least three times from beginning to end and then have loaned it to someone who needs it. There are only certain words which are valid and similies [sic] (bring me my dictionary) are like defective ammunition (the lowest thing I can think of at this time)."
That should set the cat among the pigeons.
And what about these thoughts?
"I can write it like Tolstoi and make the book seem larger, wiser, and all the rest of it. But then I remember that was what I always skipped in Tolstoi... I don't like to write like God."
There was a humility about Hemingway which is sometimes forgotten. By not telling the reader everything - by not playing God - he made a virtue of our human limitations and through those very limitations created writing that was not simply spare and vigorous but, often, very beautiful too.