Pulmonary hypertension (PH) is a pathophysiological disorder that may involve multiple clinical conditions and may be associated with a variety of cardiovascular and respiratory diseases. The complexity of managing PH requires a multifaceted, holistic, and multidisciplinary approach, with active involvement of patients with PH in partnership with clinicians. Streamlining the care of patients with PH in daily clinical practice is a challenging but essential requirement for effectively managing PH. In recent years, substantial progress has been made in detecting and managing PH, and new evidence has been timeously integrated in this fourth edition of the ESC/ERS Guidelines for the diagnosis and treatment of pulmonary hypertension. Reflecting the multidisciplinary input into managing patients with PH and interpreting new evidence, the Task Force included cardiologists and pneumologists, a thoracic surgeon, methodologists, and patients. These comprehensive clinical practice guidelines cover the whole spectrum of PH, with an emphasis on diagnosing and treating pulmonary arterial hypertension (PAH) and chronic thrombo-embolic pulmonary hypertension (CTEPH).