This book provides a comprehensive analysis of biases inherent in contemporary clinical research, challenging traditional methodologies and assumptions. Aimed at students, professionals, and science enthusiasts, the book delves into fundamental principles, research tools, and ethics. It is organized in three sections: The first section covers fundamentals including framing clinical research questions, core research tools, and clinical research ethics. The second section discusses topics relevant to clinical research, organized according to their relevance in the development of a clinical study. Chapters within this section examine the strengths and limitations of traditional and alternative methods, ethical issues, and patient-centered consequences. The third section presents four in-depth case examples, illustrating issues across diverse health conditions and treatments: gastroesophageal reflux disease, hypercholesterolemia, screening for breast cancer, and depression. This examination encourages readers to critically evaluate the methodologies and assumptions underlying clinical research, promoting a nuanced understanding of evidence production in the health sciences.