Writing is an expensive skill in the business world. Research from the National Commission on Writing showed that employers spend about $3.1 billion on remedial writing training each year.

And it's likely this trend will continue. Four years ago, data from the National Assessment of Educational Progress showed that only 24 percent of high school seniors scored at the proficient level on the writing assessment. In 2016, these Millennials are entering the work force--and that means remedial writing training may be necessary.

But before you sign up for an expensive writing course, it might be a good idea to crack open a book that can teach some of the important lessons on better, more effective business writing. Here's a list of the top seven books that can make you a better writer.

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

For more than 30 years, this book has been teaching readers the fundamental principles of writing well.

Amazon customer review: "I've read many books on writing and publishing. This book is by far the most practical, easy to understand and surprisingly entertaining to read. If I was asked to choose one book that would help someone become a better writer, it would be this one."

2. Writing That Works: How to Communicate Effectively in Business by Kenneth Roman and Joel Raphaelson

From email etiquette to political correctness, this book on writing focuses on how to write to accomplish various business objectives.

Amazon customer review: "This was a terrific book which I would recommend to all of my clients, colleagues and friends -- but not to my competitors. It gives too many good ideas on how to get your message across effectively, succinctly and clearly."

3. The Book on Writing: The Ultimate Guide to Writing Well by Paula LaRocque

Learn essential tactics for writing clearly and conversationally from an experienced writing coach.

Amazon customer review: "It seems there are a lot of people who think they can write an authoritative book on the art of writing. It is always a wonderful surprise to find one that actually knows what they are talking about and can convey their expertise is a clear and concise manner."

4. This Book Will Teach You How to Write Better by Neville Medhora

This short e-book is a crash course in writing to increase conversions and teaches readers to write in a logical, natural way.

Amazon customer review: "I'm a big fan of Neville's blog and his courses. Just like he does with his blog, with this book, he's able to get across all of his fantastic, practical advice on writing great copy while keeping it so fun and memorable. Grab it now and devour it."

5. Grammar Girl's Quick and Dirty Tips for Better Writing by Mignon Fogarty

A great resource to have on hand whenever you're writing, this book is full of quick reference tips on grammar, style, and business writing.

Amazon customer review: "I rather liked the informal style of the book and found most of my queries were answered in an easy to understand manner."

6. Write Better, Faster: How to Triple Your Writing Speed and Write More Every Day by Monica Leonelle

Practice makes perfect--and this e-book on writing can help you hone your craft to spend less time staring at a blank screen.

Amazon customer review: "A nice, analytical approach to improving your writing pace. The author shares her own experience in 'hacking' her own writing speed and shares what worked for her. The book is filled with useful examples and actionable information."

7. Blog to Win Business: How to Enchant Readers and Woo Customers by Henneke Duistermaat

Regardless of whether you have a blog or not, this e-book focuses on how to write in a way that compels readers and establishes authority within any industry.

Amazon customer review: "Don't think you're going to just read this, get a few useful tips, and then move on with your life. This can transform your writing from here on out."

Become a better writer by reading.

Grab a book off this list and start reading--you might be surprised at how quickly your writing improves as a result.