Every year, countless Jews make the pilgrimage to synagogue for High Holy Day services. They sit through hours of a service they understand little about, are mostly bored and leave the synagogue wondering just why they went in the first place.

Rabbi Alan Lew is hoping to answer that question.

His book “This Is Real and You Are Completely Unprepared” is a journey through the High Holy Days; it sheds light on their origins and the mindset of the observant.

“This could really help people understand what’s going on instead of just sitting there, you know?” said Lew, the senior rabbi at San Francisco’s Conservative Congregation Beth Sholom.

“This explains the real theology to the High Holy Days for everyone who comes to do penance sitting in synagogue and being bored to tears for long hours. Somehow, in their subconscious, that is their repentance. There is the potential of a lot more for these people.”

Lew sees the High Holy Days as a spiritual expedition in which one starts and finishes in “collapsed houses.” Yet while one begins the journey in agony, one finishes in joy.

The first collapsed house Lew refers to is the great Temple in Jerusalem; its destruction commemorated in the holiday of Tisha B’Av. Understandably, this is not a fun holiday.

Yet two months later, Jews find themselves peering at the stars through the roof of the sukkah on Sukkot. And this misshapen house is full of joy.

“Sukkot is like a guy in a house besieged by robbers. You can put more and more locks on the doors and not feel secure, and the only time you will feel secure is when the king is outside. Then you take all the locks off the doors. That’s Sukkot,” said Lew.

“You realize you’re naked in this universe and always dependent on this compassionate, all-powerful emptiness at the center of everything. That is your only source of security and there’s a kind of joy in that.”

The ability to begin and end in the same place, yet substitute a feeling of sorrow with elation, represents the transformation and enlightenment brought about by the High Holy Days.

Lew sees the journey as a time to strip away the facades people build around themselves and address life’s important issues — hence the unconventional title of his book.

“The moments that shape our lives are not the moments we’re prepared for. Life is like one big Maginot Line; we spend all of our lives preparing furiously and making ourselves more capable and working out every day for hours and generally behaving as if we could really prepare for our lives,” he said.

“But the really big events in our lives are always the ones that come out of nowhere. And we can come to realize this. Our control over our lives is much more limited than we imagine it to be, and that’s OK.”

Spiritual transformation, however, is not a magical process, and Lew is no wizard.

“If you do tshuvah (repentance) properly and enough prayers and give enough tzedakah, it doesn’t mean you’re not going to get sick,” he said. “It means when you get sick, you’ll be able to go through the process of sickness not necessarily seeing it as a punishment from God but just what life has given you at that moment.”

While Lew is hoping readers of all levels of observance pick up his book, he is still most hopeful that he might be able to convince the marginally religious of the relevance of the High Holy Days in their lives.

“There are literally millions of Jews who still feel compelled to get their tuchuses into synagogue on the High Holy Days who have no idea what it’s about,” he said.

“And what I’d like to show them is that if they knew what it was about and really took the entire journey earnestly, more and more people would take it and it would be an incredible journey that mirrors the journey of our lives, the journey the soul takes.”