If you are an engineering student, you have probably heard the name Sonntag whispered in hallways with a mix of respect and fear. The textbook Fundamentals of Thermodynamics (often just called "Sonntag") is the gold standard for engineering thermodynamics. It is also famously dense.
Buy the International Version (usually cheaper) and find the Solution Manual ( only to check your work after you have genuinely tried). Thermodynamics is a contact sport. You cannot learn it by watching; you have to do the problems with pencil and paper.
Have a specific Sonntag problem driving you crazy? Drop the chapter and problem number in the comments below.
Open to Chapter 3 (Properties of a Pure Substance). Find the diagram for $P-v-T$ surface. Stare at it for 5 minutes. If you understand that diagram, you have already beaten half the course.
Many students open to Chapter 1, see a wall of text about "systems and surroundings," and immediately feel overwhelmed. But here is the secret: You don't read it like a thriller; you mine it for gems.
