I wish I had $1000 for each person that has asked me over the years what reference material I would recommend to understand the kosher market. I know what they are thinking: volumes of Hebrew books beginning with the Five Books of Moses to perhaps answer intricate questions about the mixing of meat and dairy on manufacturing equipment. Surprise. Surprise. My answer is always: The Jewish calendar. Simply understanding the lunar calendar will answer the oft-asked question as to why the Jewish holidays fall on different dates in the Gregorian calendar we use. A good Jewish calendar will include the dates of all the significant Jewish holidays and remind anyone in the business that one does not simply step into a Jewish holiday. The Talmud in fact indicates that 30 days are necessary to prepare for such holidays as Rosh Hashanah and Passover. But as anyone who has ever been involved in kosher knows, preparing for the key holidays begins well before the Talmudic suggestion.So here’s my suggestion: Make sure that you have a good Jewish calendar in your office and do not hesitate to ask the local rabbi or perhaps an observant customer what each holiday means and what foods are eaten. Trust me that with the exception of Yom Kippur, a lot of food is consumed during the holidays and the opportunities are endless. And, of course, remember that every 7th day there is a big holiday for tens of thousands of kosher consumers. That is Shabbos or Shabbat – “And on the Seventh Day He Rested.” Genesis – Bereishit.