This text, the first comprehensive text in philosophy of science in many years, is divided into two books. Book I deals with traditional problems in the philosophy of science: logic, explanation, and epistemology. Book II presents various schools and systems of thought from the philosophy of science. Prominently featured are: rationalism, empiricism, logical positivism and constructivism. The text offers both breadth and depth, but is written in a clear and accessible style, making it appropriate for philosophy of science courses at the undergraduate and graduate levels.