In Daven Your Age, Rabbi Yehoshua Grunstein makes a sincere attempt to respond to a well-known dilemma; the fact that many adults have failed to grow up in their approach to prayer and still see it from the perspective of when they last studied it, in grade school. Rabbi Grunstein therefore attempts to reintroduce many aspects of this most basic element of Jewish spirituality in a way that is intended to appeal to adults and their concerns.
The book is divided into five sections. The first section is a general overview of basic ideas about prayer. The second section discusses the importance of communal prayer, and the next three sections discuss various aspects of the daily morning prayer service. Each chapter is followed by a brief summary of the topics covered, and these summaries are then collected as a final appendix to the entire book.
One of the difficulties I had when reading this book is that it is fairly obvious that I am not part of Rabbi Grunstein's target audience. While I will readily admit that I am very far from where I ought to be with regard to my prayer, I found the topics that Rabbi Grunstein discussed to be very elementary and I often felt that he was glossing over many major issues, topics, and sources that I would have expected to be covered. This was especially true in the first section of the book. In my opinion, the final three sections, which deal with the details and language of the prayers are far stronger than the first two.
I had similar issues with the style of presentation, which I often felt was excessively informal and "chatty".
However, ultimately these are a questions of taste and style, and it is difficult to judge whether Rabbi Grunstein made the right decision in these areas, especially as I am not really clear on the nature of his target audience.
While I have a number of criticisms of the content of the book, most of these criticisms are about minor details that aren't really worth detailing. The one exception is in the first chapter of the book, where Rabbi Grunstein incorrectly assumes that the Biblical concept of "service of the heart" refers exclusively to a spontaneous, emotional experience. Rabbi Grunstein then compounds this error by reading this idea into the words of two major Jewish authorities, Maimonides and Nachmanides, in their debate over the Biblical obligation to pray. While there is no question that spontaneous, informal prayer is a very important aspect of Jewish prayer, there is no question whatsoever that formal, structured prayer is also a fulfillment of the Biblical commandment of "service of the heart." The debate between Maimonides and Nachmanides is on the nature of the obligation, but all sides agree that all sincere prayer, whether spontaneous or formal, is a fulfillment of the commandment to serve God "with all your heart."
However, with the exception of this one error (which, unfortunately, is in the first chapter of the book), the book is reasonably well-done. The basic themes that Rabbi Grunstein focuses on are all valid and important (even if I would have presented them somewhat differently), and I am sure that there are many people who would benefit from reading his book.