Pulmonary arterial hypertension is a group of diseases which forms a small subset of those with elevated pulmonary artery pressure (pulmonary hypertension). The recent development of selective pulmonary vasodilator has lead to a substantial resurgence of interest in what have been previously regarded as rare and incurable diseases. This review aims to describe the spectrum of pulmonary vascular diseases, the evolving understanding as to pathogenesis, the evolving evidence of efficacy for drug therapies, trying to put this into a contemporary Australian context. Several key pathogenic pathways may be involved: prostacycline, Nitric Oxide-cGMP-phosphodiesterase 5 and endothelin- all of which are exploited for therapeutic benefit by newly available drug therapies. A recently modified classification system reasserts the importance of precise diagnosis. The cardinal symptom of exertional dyspnea warrants careful evaluation in an attempt to prevent (frequently occurring) substantial delay in diagnosis. Echocardiogram is the cornerstone of screening for pulmonary arterial hypertension; however, a detailed evaluation including a carefully performed right heart catheterisation with sufficient data to allow calculation of pulmonary vascular resistance is key to accurate diagnosis. These new approaches to therapy are already substantially improving quality of life and prognosis.