Pneumonia is a detailed guide that explains the causes, symptoms, diagnosis, treatment, and prevention of this common and potentially serious lung infection. The article begins by defining pneumonia and describing how it affects the air sacs in the lungs, leading to symptoms such as cough, fever, and difficulty breathing. It explores the various causes of pneumonia, including bacteria, viruses, and fungi, and discusses the differences between community-acquired and hospital-acquired infections. The guide provides insights into the diagnostic process, including chest X-rays and laboratory tests, and explains treatment options such as antibiotics like azithromycin (Zithromax) for bacterial infections and antivirals like oseltamivir (Tamiflu) for viral cases. Preventive measures, including vaccines and healthy lifestyle practices, are emphasized to reduce the risk of infection. The article also highlights potential complications and addresses the role of genetics in susceptibility to pneumonia. Organized to provide a clear understanding of the condition, this guide serves as a resource for patients, caregivers, and the public. The information is presented in simple terms to ensure it is easy for all readers to understand and apply.