Popper's theory of science has been widely misunderstood and poorly represented in the literature on philosophy of science, over the last three decades. The reader can find numerous apparently devastating criticisms directed at the core concepts of this theory (falsifiability and its role in the solution to the problem of induction, corroboration and verisimilitude). Philosophy-minded readers who are not very familiar with the writings of Popper and who form their philosophical judgement based on the views that are dominant in the secondary literature, usually conclude that Popper's theory of science is untenable. This book discusses the main issues in Popper's theory of science and, after giving a careful characterization of each issue, examines the main objections that have been raised against them and offers ways of circumventing them. This task is undertaken by means of a thorough analysis of the central concepts of Popper's theory, namely, falsifiability (as a criterion of demarcation between science and non-science and as a means to rescue the rationality of scientific knowledge), corroboration and verisimilitude. Once the central concepts of Popper's theory of science are properly analysed and restated, the author offers additional arguments for the tenability of the thesis according to which science without induction does not necessarily lead to irrationalism. There are some subsidiary contributions in the form of amendments to Popper's definitions, especially to his qualitative definition of verisimilitude. The book shows that Popper's theory can guide us again to a better understanding of the aim and the structure of science.