Book excerpt: Singer and actors are a unique group of performers, relying almost entirely on their voice for the professional livelihood. Jet lag, amplification, allergens, stress, pollution, and vocal strain all affect vocal performance. Written for the performer, the teacher, and the vocal coach, Care of the Professional Voice offers clear explanations and medical advice on vocal problems and vocal health. Care of the Professional Voice is written by experts in laryngology in the United States and Great Britain. This second edition includes a singer's guide to self-diagnosis.