If there is a constant in the history of Latter-day Saint temple worship, it is change. Language used, covenants made, clothing worn and meaning ascribed to all of it — each has evolved since the early 1830s, when Joseph Smith introduced the idea of sacred rituals beyond baptism and confirmation. In his newly published book, “Holiness to the Lord: Latter-day Saint Temple Worship,” historian Jonathan Stapley explores those changes in greater detail than any other work to date. Those changes have not only practical but also theological implications, he argues, for members of The Church of Jesus Christ of Latter-day Saints in the past and the present.