This document provides an introduction to a handbook for firms seeking to source from smallholder farmers in a sustainable manner. It notes the challenges of meeting growing global food demand given constraints on arable land and declining yields. Sourcing from smallholder farmers represents an opportunity for firms to expand supply and improve productivity, though it also presents challenges related to quality, social and environmental impacts, farm management skills, and transparency. The handbook aims to provide guidance to firms on developing successful partnerships and programs with smallholders.