Medicinal plants have been used for health care since long time ago. It has been documented and passed down through the generations for over 4,000 years. Numerous medicines have been made available for many important global diseases since scientific investigations began in the early part of the 19th century. Now, in the early part of the 21st century, an urgency to explore these traditional remedies at molecular level by application of biotechnology to meet patient needs the world over has emerged. The technologies which can be applied to elucidating the effectiveness, safety and efficacy of herbal plant medicines have been evolved. At the same time, much knowledge of the use of plants in various health problems remains to be recorded. This volume will present an illustrative overview of some selected areas of herbal plant medicine and the historical and contemporary use of herbal medicinal plants. It will also indicate some of the critical areas of ongoing research which are transforming the study of herbal medicinal plants with a view to enhance the quality, efficacy to restore health for the majority diseases of the people on Earth.