I wish I had a copy of this text in graduate school when I was taking philosophy of science courses, because the sections on probabilities and inductive logic, and the logic of hypothesis testing and confirmation, are so much better than you find in most critical thinking texts.
This isn't surprising, since the author is a distinguished philosopher of science who has a long familiarity with the issues that animate discussion in that field. It's not uncommon for textbook writers to write the texts that they wish they had available to them, at the early stages of their career.
The text is also unusual in that the detailed discussion of inductive reasoning (generalizations, causes, analogies, hypothetical reasoning, statistical reasoning, etc.) comes before the detailed discussion of deductive reasoning (propositional and categorical logic). Again, this is the sort of choice that a philosopher of science would make, given how fundamental inductive reasoning is to scientific reasoning, and common sense reasoning about the world.
As new editions of this text have come out, Salmon has added more material on the psychology of human error (e.g. "probability blindness", in the section on reasoning with probabilities), which is good to see, but it's still mostly window-dressing.