> we know what the Overdrive gear in automatic-transmission cars means, and why you use it to pass a truck on the highway
That is not what overdrive is [1]. Overdrive is the very high gear that lets you nearly idle at highway speeds. Stepping on the gas would strain the engine, until the automatic downshifts, which is what the author seems to describe.
EDIT: it seems strange, coming from a miata driver, since those gearboxes definitely lack an overdrive, requiring high RPMs at highway speeds (like a racing transmission, tight ratios)
Your definition of overdrive is slightly incorrect. Overdrive simply means that the overall ratio between the input to output shafts of a transmission is less than 1.0 (meaning the wheels of the car are spinning faster than the engine).
By this definition the Miata does have an overdrive as most generations have a final ratio of around 0.85 in top gear.
Your definition is correct, but your conclusion is incorrect.
The wheels of the car are not spinning faster than the engine (in the overwhelming majority of cars) because there is still a final drive ratio between the output shaft of the transmission and the wheels. That is rarely taller than 2.50:1 and often greater than 3:1.
Look at the revs per mile in a tire's specification, drive that car at 60mph, and see that the engine RPM is higher than the revs per mile figure, even in the tallest overdrive gear that you have.
Yes, this was very jarring, leaving exactly the opposite impression the author was aiming for at that point! My memory of learning to drive a manual was also not nearly as fraught as the author describes, and I don't claim any particular driving prowess (this could be a function of the car, though, I learned on one that I suspect was more forgiving).
> we know what the Overdrive gear in automatic-transmission cars means, and why you use it to pass a truck on the highway
That is not what overdrive is [1]. Overdrive is the very high gear that lets you nearly idle at highway speeds. Stepping on the gas would strain the engine, until the automatic downshifts, which is what the author seems to describe.
[1] http://www.wikiwand.com/en/Overdrive_(mechanics)
EDIT: it seems strange, coming from a miata driver, since those gearboxes definitely lack an overdrive, requiring high RPMs at highway speeds (like a racing transmission, tight ratios)