Symptoms vary with the organism, the amount of lung involved and the host’s inflammatory response. A sudden febrile illness with rigors, productive cough, pleuritic pain, tachypnoea and focal chest findings suggests a typical bacterial CAP, classically involving *Streptococcus pneumoniae*. A slower illness with dry cough, headache, myalgia and malaise may occur with atypical organisms, but the distinction is not reliable enough to select treatment by symptoms alone. Crackles may reflect air moving through fluid-filled or reopening alveoli. Bronchial breath sounds heard over a peripheral lung field, egophony, whispered pectoriloquy and dullness to percussion support consolidation. A patient can still have extensive pneumonia with few auscultatory findings, particularly early in illness, in older adults or when the process is diffuse. Legionnaires’ disease should prompt questions about recent hotel, hospital, cooling-tower, plumbing or hot-water-system exposure. Diarrhoea, headache, myalgia, hyponatraemia or confusion can accompany the pulmonary illness. Legionella is acquired by inhaling or aspirating contaminated water aerosol; routine person-to-person spread is not the usual concern. A negative urinary antigen does not exclude legionellosis because the commonly used test detects *L. pneumophila* serogroup 1...