Pharmacologists are researchers who study the composition, properties, usage and toxicology of drugs, and analyze how the drugs interact with biological systems. The main aim of undertaking research pharmacology is to understand how drugs work and how they can be safely utilized for maximum efficiency. Pharmacologists study the drug design, its molecular and cellular mechanisms, and chemical biology. The two main branches of pharmacology are pharmacokinetics and pharmacodynamics. Pharmacokinetics focuses on how the body affects the drug after administration and what chemical changes happen to the substances in the drug after it enters the body. Pharmacodynamics is the study of the effects of the drugs on the body and on the microorganisms present in the body. It analyses the relationship between drug action and effect. Pharmacologists undertake two main types of research: in vitro research that involves using cells or animal tissue, and in vivo research that uses whole animals to predict the effects of specific drugs on human beings. Areas of specialization in this field include clinical pharmacology, neuropharmacology, and regulatory pharmacology. Read on to browse through a list of world famous pharmacologists and read their biographies and timelines.