#1 On Writing Well: The Classic Guide to Writing Nonfiction by William Zinsser

#2 Finding Your Writer’s Voice: A Guide to Creative Fiction by Frank & Wall

#3 Crafting The Personal Essay: A Guide for Writing and Publishing Creative Non-Fiction
by Dinty Moore

#4 On Writing: A Memoir of the Craft by Stephen King (Also memoir)

#5 Page after Page by Heather Sellers

#6 The War of Art: Break Through the Blocks and Win Your Inner Creative Battles
by Steven Pressfield

#7Writing Down the Bones: Freeing the Writer Within by Natalie Goldberg

#8 Bird by Bird: Some Instructions on Writing and Life by Anne Lamott

#9 The Elements of Style (4th Edition) by William Strunk and E. B. White

#10 The Curious Case of the Misplaced Modifier: How to Solve the Mysteries of Weak Writing
by Bonnie Trenga

This list is culled from an article of the same title by Marya Jan. She is a freelance blogger and online copywriter.