Alvin Mark Tan is an artist and content creator based in Singapore, and he's my friend from Urban Sketchers Singapore. I've featured a few of his books before, namely La Kopi, CIao Firenze! and Thirty Days on the Camino.
A Travel Guide to Sketching on the Move is not exactly a book but a huge foldout. When unfolded, it looks larger than A2.
The foldout features a collection of drawing tips for sketching on the go, basically, sketching outdoors. His loose and free sketches are accompanied by personal stories and tips on drawing people, details, colours and values, and on places where you can draw.
This foldout is meant to be a quick start to urban sketching. The tips are short so it's not meant to be a comprehensive book on techniques. The goal here is to inspire and get you interested to draw outdoor whenever you have the time, or don't have the time.