This book redirects attention to a truth largely ignored by recent criticism—that Shakespeare's excellence as a playwright is inextricable from his excellence as a poet. It explores the diverse means by which Shakespeare's poetry enriches his drama, illustrating how particular words in a particular order render his dialogue distinctive and create supreme literary and dramatic value. By examining many passages, long and short and from a variety of Shakespeare's plays—comedies, histories, tragedies, later plays—the author aids understanding of the poetic effects that make Shakespeare preeminent. His analyses, alert to textual variants and cruxes, are illuminated by comparisons: Shakespeare's early verse is compared with his later verse and samples of Shakespearean dialogue are compared with versions in later adaptations, in modernizations, and inferior quarto texts, as well as with contributions by his co-authors to collaborative plays. The contrasts throw into relief the surpassing vitality and expressiveness of Shakespeare's own language. Since the rhythmic vitality of Shakespeare's verse is essential to how and what it communicates, an appendix on the principles of iambic pentameter is included to support those aspects of the analyses that refer to acoustic subtleties.