I can easily see how this book would be indispensable for those new to the Catholic faith. In fact, I was tempted to buy this book for the entire RCIA class this year (pecuniary interests prevented this, of course).
What may not be so obvious is the value to cradle Catholics. So many details of the Mass are lost in the fog of CCD & "Religion Class" (in my day, calling it "Catechism Class" would have offended the hippies and ex-nuns). Details on the meaning and purpose of bowing vs. genuflecting, signs of the Cross, etc., were invaluable, as was the emphasis on the liturgical calendar and historical origins of different components of the Mass.
The author does a great job of focusing on the Real Meaning, as opposed to simply detailing the mechanics. The Scriptural storyline provided is relevant and helpful, as are the personal anecdotes. Also helpful was the admonition to the overscrupulous. It was particularly appropriate for me to be armed with humility when I began to notice fellow parishioners genuflecting to the empty tabernacle on Good Friday.
The only thing missing from this book is an appendix of prayers during Mass (before & after are provided). While referencing the text of the Gloria, the Confiteor, etc., the full text was not provided. Obviously these can be obtained elsewhere, but it would have been nice to have them for reference in this book.
In summary, Dubruiel's work ought to provide an entertaining and instructive read for any Catholic - cradle, convert, or returning, as well as providing a full explanation for non-Catholics wondering what the "smells & bells" are all about.
Actually, if you go to the Amazon link, you can click on new and used copies and I'll sell you a new copy cheaper than they are selling it for ($9.00) and if you'd like to give the book as a gift to someone I'll even autograph it specifically to that person. You can order it through Amazon but you'll be getting it from me.