The present volume is a collection of original articles of high quality on the Philosophy of Science by philosophers and scientists of international repute. As the title of the book suggests, it looks at the various points of view of leading practitioners, as well as philosophers on the nature and structure of our knowledge of the physical world. The present work brings forth the fundamental ideas of Bacon, Galileo, Newton, Descartes, Popper, Einstein, Thomas Kuhn and several other leading scientists and philosophers.