Mechanical Vibrations (Addison-Wesley series in mechanical engineering)

What started off as a clear, concise text that fully explained basic concepts quickly degraded into a confusing and unhelpful text that seemed to assume you already knew the topics and treated it as a review. Example problems are completely worthless as Rao often skips dozens of steps at once, assuming the reader is already a pro at modeling complex physical systems. To make matters worse, there seems to be a distinct lack of explanations and plain definitions for many terms that are randomly introduced into the topic. Modal shapes, eigenvectors/eigenvalues, etc. are all introduced with little to no background information. The only reason I'm giving this 2 stars instead of 1 is because I could potentially see the book's value as a review text or reference, but as the main text for an introductory course on vibrations... Well, let's just say you better have a much better teacher than Rao is a writer.