Rarely does a textbook transcend the ordinary to be universally considered a “classic”. The esteemed A Handbook on Stuttering, now in its 6th edition, continues to be the only existing work that offers a comprehensive review of evidence-based knowledge about the etiology, nature, and treatment of stuttering. Since the last edition was published there have been numerous important advances in research on stuttering, particularly with regard to brain research and language development. This edition captures these new developments, without losing the historical information that makes it so unique.