I can't speak for the book, but I was a participant in a mindfulness study a decade ago. The biggest thing about it, I've taken, is that you recognize your feelings and acknowledge how they are causing you to behave. It doesn't transform you into an emotionless monk, but rather aims to make you aware (or mindful) of how you and your actions are being motivated through your emotions and non-awareness. For example, a mindfulness-driven diet would place emphasis on cultivating awareness of mindless snacking and aim to make you aware that you don't actually need to be eating at the moment - you are just snacking out of boredom or instinct.
With regard to emotion, like I said, mindfulness isn't meant to eliminate emotions, or even eliminate negative emotions. If something makes you mad or angry, you may carry that emotion into later tasks. Mindfulness is about recognizing the anger, acknowledging it, but understanding not to project onto other things.
There's probably more to it, but I was trained in mindfulness by proxy of martial arts (that was the study) [1]. I never studied it outright and only took a Mindfulness Attention Awareness Scale survey a few times over a few years. The paper I linked might give you some ideas on what mindfulness is.
With regard to emotion, like I said, mindfulness isn't meant to eliminate emotions, or even eliminate negative emotions. If something makes you mad or angry, you may carry that emotion into later tasks. Mindfulness is about recognizing the anger, acknowledging it, but understanding not to project onto other things.
There's probably more to it, but I was trained in mindfulness by proxy of martial arts (that was the study) [1]. I never studied it outright and only took a Mindfulness Attention Awareness Scale survey a few times over a few years. The paper I linked might give you some ideas on what mindfulness is.
[1] https://journals.sagepub.com/doi/pdf/10.2466/22.23.PMS.116.1...