Special Issue (book/journal reprint) of established and newly-developed instruments for measuring spirituality and religiosity across diverse populations, traditions, and clinical contexts, serving as a resource for spiritual care research.

KEYWORDS: open access / free access; active duty military / veterans; attachment theory; Attachment to God Inventory (AGI); attitudes toward religion; Catholics; clinical setting; elderly; evaluation; exploratory factor analysis; factorial structure; gratitude; growth; healthy persons; Islam; measurement; moral injury; Muslims; post-traumatic stress disorder; psychometric properties; questionnaire; religiosity; religious beliefs; scoping review; Spiritual Health and Life-Orientation Measure (SHALOM); spiritual jihad; spiritual needs; spiritual struggles; spiritual well-being; spirituality; structural equation modeling (SEM); styles of attachment; transcultural adaptation; validation