@alberto.abbate Thank you so much and you are very welcome! I'm glad you enjoy my work.

The first and only book that comes to mind would be Kimon Nicolaides' book, "The Natural Way to Draw." I'm a bit reluctant to recommend it, however, only because it is a workbook with a clearly defined regimen of study which is very structured and requires a lot of time. (Check out some of the reviews for this book on Amazon.com and you'll see what I mean.) He talks about gesture drawing but it is only a part of his overall approach. I tried to go through it, but didn't get very far, mostly because I was doing basically the same thing every day in art school! such as... gesture drawing, contour drawing, mass drawing. I learned how to draw the best way possible, as I wrote above, with great instructors: Douglas R. Graves, Bill L. Parks, and Joseph Vanden Broucke. You might check out Graves' books, too, although I don't recall how much - or even if - he talked about gesture drawing. Mostly, just know that very little knowledge is required to learn gesture drawing. It's a matter of practice, practice, practice. There ARE some YouTube videos that look very good. Just do a search and I'm sure you'll find some. Hope this helps and good luck!