The diagnosis of HIV infection is missed too often, with significant costs to patients and the community. Could it be HIV? gives practical advice about the detection of unsuspected HIV infection following clinical presentation. Each section is written for doctors by colleagues with extensive experience in HIV medicine; many illustrative case histories are drawn from their personal records. The chronology of HIV-induced disease is a useful framework for interpreting the many possible clinical clues to HIV infection which, together with lifestyle clues, contribute to decision-making about the rational use of HIV testing.