What are the best books about writing?

Maria Popova, the genius behind Brain Pickings, put together a seminal list of books about reading and writing. It includes classics like Anne Lamott's Bird by Bird and Strunk & White's Elements of Style. If you want a very economical MFA in writing, here's your syllabus.

I think Ezra Pound's ABC of Reading needs to be on the list. What else? Tell us in the comments.