[mesaframe]

Whatever the author mentions is part of meditation. But observing the mind requires concentration too otherwise it will wander away with thoughts.

Anyway, if you feel connected with such kind of things then I'll heavily recommend to do meditation.

[godDLL]

Concentration is a loaded word. It is not black and white, but feels like you're talking about a value that goes from zero to one possibly? How do you think about it?

I came to think of it in terms of attention. In a model where your awareness of time, or of change is conditional on shifting your spotlight of attention it can be defined usefully, I think.

So, in such a model your concentration is conditional on your paying attention to where your awareness is not pointed. To the interplay of things outside your spotlight of awareness.

The processes that are you but outside of the seat of your awareness already have workable models for all of that. They have good guesses. Your sensory will enrich those guesses and flow them into your reality as givens.

If you think of it like that there is a clear difference between paying attention to something, and expanding your perception of the present moment by concentration.

Sometimes I hear people use the c-word to describe uninterrupted time dedicated to a task. That is to say focus. Exclusionary attention.

How do you think about it?

[mesaframe]

Yes, concentration is attention. There are levels of concentration. With the final being Exclusive attention to the object.

Again meditation goes more deeper into the model.

If you are curious about it I'll suggest you to read the book. The Mind Illuminated by Culadasa.