Klee is a prof. of philosophy at Ithaca College. He states somewhere near the end of the book that his perspective is that of holist realism.
Throughout this book he deals with the debate between realism and anti-realism, giving answers (a real apologetics) against anti-realist arguments (in particular against philosophers of nature such as Kuhn, Van Fraassen, Laudan.., and against postmoderns and feminists) In the conclusion of the book the author ends by stating his optistism for natural science which he by far sees as the highest achievement and hope.
I find this book valuable when taken as a book about the debate between realism/antirealism, or as a defense of realism. But I do not find it valuable as a introduction to the philosophy of "science". The author does not define what he means by "science" (this word used to mean something like "organized knowledge" and used to include theology, history, philosophy - it is only since about a century or more that the influence of positivism/kantianism in the anglo-Saxon world has reduced it to the modeling of natural or social patterns). Besides, he starts right away with positivism, , skipping thousands of years of science and philosophical debate (although he sometimes mentions some less recent authors), and continues with the 20th century debate about realism, letting many current issues aside.
I have nothing against the fact that the author defends realism so much, but then I expect him to be honest and clear. I think this book should have been called something like "An Introduction to the Philosophical Debate about the Objectivity of the Natural and Social Sciences: a Realist Perspective."
BTW, I sometimes had the impression the author is committed to materialism or even to scientism, but I may be wrong about this.