If you need the content of Ohanian Physics Volume 3, you have legitimate options that are often superior to a bootleg PDF.

Before diving into the specific content of Volume 3, it is essential to understand the author's philosophy. R.C. Ohanian is not just a textbook writer; he is a physicist deeply concerned with the foundations of the field.

Unlike the "kitchen sink" approach of some massive introductory texts that throw every formula at the wall to see what sticks, Ohanian’s writing is characterized by selectivity and depth. He assumes intelligence on the part of the reader. Volume 3 does not coddle; it challenges. However, unlike graduate texts (like the notoriously dense Reif or the terse Landau), Ohanian provides the scaffolding necessary for a junior or senior undergraduate to climb the mountain of Modern Physics.

Interestingly, Kenneth S. Krane (who co-authored later editions of the Ohanian series) wrote a standalone book titled Modern Physics. If you need Ohanian specifically for the modern physics chapters, Krane’s book is 95% identical in sequence and rigor. You can often find the Instructor’s Edition or older printing for $20 used. Search for "Krane Modern Physics PDF" (legally, via publisher samples).