“Now-ness” is the state of ideal attention. That is, it is a state of being where all that exists is the present moment, without any thought of past or future. It is paying total attention to what you are doing in the moment that you are doing it. If you are eating for example, just eat. If you are reading, just read. If you are eating and you are thinking about your bills, or what is on television tonight, then you are not in a state of now-ness. If you are reading and you are not totally concentrating on the act of reading then again, you are not in the present. Regardless of what you happen to be doing, if you are thinking about something else, then you are not attentive and not in a state of now-ness
When you are not attentive, not here and now, your present peace of mind may be disturbed by some oncoming future event for no good reason. For example: Remember when you were in high school and you had a very important test coming? It was Friday and the test was to take place on Monday. That night you went to a party and enjoyed the evening for several hours when it happened! What happened? Suddenly, thoughts about the impending test darted across your mind...