Those books, as far as I know, are limited to engines and operation and maintenance. The OP said this:
Would like to learn about aviation engines and mechanics such as on the Cessna 150 172, not wanting to be an A&P. What book would someone recommend to read to learn how the aircraft functions mechanically.
I took that to mean the whole airplane, and the Sky Ranch books don't cover that. The Aircraft Systems book I posted does.
The index in that book, which I have here (previous edition to the new one) covers these topics in considerable detail:
Physics
Aircraft engine types and construction
Reciprocating engine theory of operation
Engine lubrication and cooling
Propellers and governors
Fuels and fuel systems
Power management
Supercharging and turbocharging
Pressurization and high altitude operations
Electrical principles
Electrical components
Aircraft electrical systems
Hydraulic systems and landing gear
Pneumatic and deicing systems
Aircraft structures and flight controls
Weight and balance, inspections and pilot maintenance
Aircraft instrument systems
450 pages of all that. Many subtopics under each of the above headings. For $40 it's an unbeatable resource for pilots. Aircraft service manuals are good, but they don't explain
why things are the way they are.