Life, he realize, was much like a song. In the beginning there is mystery, in the end there is confirmation, but it's in the middle where all the emotion resides to make the whole thing worthwhile.

This quote is saying that life is like a song. At the start of a song, there is a sense of mystery and excitement as the music begins. As the song progresses, there are all kinds of emotion as the story unfolds, making the song enjoyable and worthwhile. In the end, there is usually some kind of conclusion or confirmation, making the listener feel satisfied. Life is similar, in that at the start there is a sense of uncertainty and adventure but as life progresses, experiences and emotions make it enjoyable and worthwhile. Eventually, life ends with some kind of conclusion or confirmation, making it an overall rewarding journey.