There is extensive literature available on pleural effusions and in recent years there has been significant developments in their diagnostic evaluation. The use of point of care ultrasound, pleural manometry, and medical pleuroscopy has expanded over the last decade. The goal of writing this book was to become a source or reference for clinicians who manage patients with pleural effusions. Pleural space contains minimal amount of fluid and physiological processes keep a constant equilibrium so that it remains as such. Pleural effusions develop as a result of processes that disrupt this fine balance, as in heart failure, infections, and malignancies, which account for majority of the pleural effusions. Besides these three common causes, pleural effusions cause symptoms in many other conditions, some of which are common regardless of the etiology of the pleural effusion, such as, dyspnea and cough. Diagnosing the etiology becomes important as management can vary depending upon the cause. In some situations, involvement of the pleural space portends a poor prognosis, such as in malignancies and treatment focuses on symptom relief. The chapters in thise book span over a wide range of topics involving pleural effusions. Initial chapters focus on clinical presentation, radiology, diagnostic evaluation, and classification of pleural effusions. There is a chapter on malignant pleural effusions, pleural infections and empyema, rheumatological causes of pleural effusions and tubercular and fungal pleural effusions. Pleural manometry is an important tool in the work-up of a trapped lung and an entire chapter is dedicated to this topic. Another chapter focuses on interventional procedures including pleuroscopy. The last two chapters go over cases of pleural effusions which cover many of the topics covered in the book. The book compiles recent literature on pleural effusions with an aim to help clinicians manage patients with pleural effusions effectively.