THE CHURCH of the Latter-day Saints has habitually been regarded by outsiders as esoteric, cultish, and deeply suspect. Once, Mormons were physically attacked for their beliefs. Now, the religion is treated more respectfully, although still with an edge of condescension. If it is made fun of, as in the Broadway hit “The Book of Mormon,’’ that can pass as a sign of acceptance in a culture that depends on the Catholic nun as a comedic staple.

Yet the religion remains mysterious to most gentiles, as Mormons refer to non-members. Secret rituals, authoritarian structure, sacred texts that seem eccentric, curious doctrines about the dead, a contested past that includes polygamy, and certitude of faith that can seem intolerant all exist side by side with impressive growth in membership, positive values that lead to undeniable success in business and family life, and the powerful arrival of Mormons on the American political scene. Mitt Romney’s status as front-runner for the Republican presidential nomination, together with the long-shot candidacy of Jon Huntsman, make the Mormon religion a fact to be reckoned with in politics today.