Understanding Perspective (The Urban Sketching Handbook)

A good sketch starts with good bones. Often challenging and overwhelming to sketchers, the fourth book in the Urban Sketching Handbook series uses drawings and simple steps to explain the concepts of perspective in practical and useful ways for on-site sketching. Most books are either too abstract or don't provide enough information that relates to what you actually do when you're out in the busy, wide world about to start a drawing.

Where do you start? How do you edit what you see to flatten and shrink it onto your paper? How does perspective work?