The Copywriter's Handbook, Third Edition: A Step-By-Step Guide To Writing Copy That Sells by Robert W. Bly Copywriting: Successful Writing for Design, Advertising, and Marketing by Mark Shaw and The Idea Writers: Copywriting in a New Media and Marketing Era (Advertising Age) by Teressa Iezzi
Um ... obviously the top copywriting book is the Bible. Duh! Over a million copies sold. Wait, that's McDonald's. Then the best copywriting book must be a cheeseburger. Yeah. That's it. A cheeseburger. I like the late Pat Quinn's books. The Secrets of Successful Copywriting and Word Power.
Breakthrough Advertising - Eugene Schwartz 12 Month Millionaire - Vincent James Advertising Magic - Brian Keith Josiah.
For me, although it's not aimed at just copywriters, but as a copywriter, I find it invaluable - it's called "The Queen's English And How To Use It" by Bernard C. Lamb. What is good English, and why do we need it? The Queen's Englishshows how language, used properly, has enormous power to inform and inspire. Used incorrectly, however, it has the same power to baffle and bemuse. The book is available on Amazon (http://amzn.to/2uJ9OL), that's where I bought mine.