This Medical Nursing book covers many acute and chronic diseases that affect adult health. The first part of the book begins with a section on "medical nursing practice" where students can learn about the scope of medical nursing. The second part of the book deals with "homeostasis," which consists of basic information that allows students to understand the disorders associated with body systems. The next eleven parts of the book deal with the diseases of each body system such as hematological diseases, cardiovascular diseases, respiratory diseases, endocrine diseases, gastrointestinal diseases, urinary diseases, neurological diseases, oncological diseases, musculoskeletal diseases, immunological diseases, and skin diseases. Each part begins with the assessment chapter and then continues with some important diseases related to the system that that are important to health care professionals as they become more prevalent and important worldwide. Chapters dealing with the assessment of a body system include a brief overview of anatomy and physiology (with emphasis on information that promotes understanding of signs and symptoms), health history, and the impact of disease on functional health patterns (Gordon model). However, the methods of physical examination to evaluate diseases of the appropriate systems and the expected findings are also covered. The chapter also covers common diagnostic tests, expected findings, and related nursing tasks. The chapters on disease begin with a brief introduction that includes disease definition, pathophysiology, and epidemiology. The chapter then continues with clinical manifestations, diagnostic studies, and care management. If patient education is an important aspect for the disease, the chapter also includes patient education. In addition, the book contains two other parts: Integrative Therapies and Medical Nursing Specialties. It is now common knowledge that integrative therapies are offered in health care facilities alongside conventional medicine, and there is a great demand for them. Especially in Asian societies where these methods are widely used, nurses should have a solid knowledge base on the subject. In the part about the specialties of medical nursing, the sub-specialties of medical nursing are discussed. The fact that our faculty, which was founded in 1961 and is one of the most prestigious nursing schools in Turkey and has educated numerous nurses at both the bachelor's and master's and doctoral levels, is introducing an English-language nursing program in 2020 motivated us to write this book. When we were looking for books to use as textbooks for our program, we found that although there were many books on medical-surgical nursing on the market, they were mostly intended for graduate students and the amount of knowledge was challenging for undergraduate students. We wanted to create a more compact and student-friendly book (a shorter book with basic information). Thank you to the support of many faculty members working in nursing schools in many regions of Turkey, we were able to realize this vision. We thank each and every one of them. Although the goal of this book is to create course material for students in our own program, we think that students around the world will benefit from this book.