The landscape of classic Jewish thought—and therefore, of—is painted with a finite set of themes and motifs. For many of these themes we have standard terminology, single words or phrases that pack a whole lot of history, controversy and weltanschauung. Others appear in multiple guises, awaiting your discovery that within them hides a single soul.

Recently, I began a project to gather the most vital of these theme-words and provide for each one a concise yet enlightening overview. From my perspective, it’s an exciting challenge: to isolate the core elements of each subject and present these with clarity for expert and novice alike. For our readers, I hope this lexicon will render much of our heavier material a little lighter and open up new portals of knowledge. Reader comments provide an opportunity for collaboration between author and audience—since we are, after all, dealing with a dynamic, live media.

If it’s Torah, it must have practical application. And so I’ve attempted to present not only the metaphysics, but the applied physics of each concept for life-on-Planet-Earth. In addition, each entry is sprinkled with links, branching out to the vast library of essays, audio and video we’ve collected here over the years. For the searching mind and soul that seeks yet wider vistas, I hope to see many new pathways forged as this work progresses.