A: It is likely a mislabeled torrent or a malicious .exe pretending to be a PDF. Legitimate PDFs never need installation.

The Samuelson-Nordhaus 19e is divided into 7 parts, 34 chapters:

: How the government and central banks use taxes, spending, and interest rates to manage the economy. The Neoclassical Growth Model

If you want the soul of Samuelson without the piracy guilt, buy the 1948 first edition reprint. It is a history book now, but reading Samuelson explain Keynes before it was cool is a joy no PDF scan can replicate.