I recently finished reading one of the manliest book ever and no it's not a romance book (BTW I like to read Romance novels too). The book is called The Way of The Conscious Warrior: A Handbook For 21 Century Men by P.T. Mistlberger. In a nutshell, P.T. talks about 21st-century men and how they act compare to back then. There are specifications to the types of men level he talks about, from being masculine to weak. The book is filled with war history, warriors from different cultures, and modern-day warriors. Also, this book has lots of guidance such as warrior qualities, masculine core, 8 essential men secrets, and more manly disciplinary. I personally believe this book is geared towards martial artist, those who seek self-discipline and are interested in war history. Check out this website for the full review and many other more reviews- What Do You Get When You Mix Testosterone and History? This Book
If you like to read romance books, then I highly recommend "The Butt Pirate". Don't let the name full you, it's full of romance and intrigue!