This proposal addresses the NIH's initiative to advance innovative structures and processes to support dying persons and their caregivers by profiling the challenges of recognizing and responding to distressed family caregivers during brief interactions with formal caregivers. Specifically, we will: Aim 1: Explicate how health care providers recognize, interpret, and respond to caregiver uncertainty across three distinct end-of-life trajectories: an expected-death trajectory (amyotrophic lateral sclerosis [ALS]), an unexpected-death trajectory (heart failure), and a mixed-death trajectory (lung cancer);Aim 2: Compare and contrast the family caregivers'experiences of uncertainty over the course of 12 months of end-of-life care with the health care providers'recognition, interpretation, and response to caregiver distress during their interactions;and, Aim 3: Translate findings from Aims 1 &2 into a theory-guided, research-based assessment and intervention protocol to support distressed family caregivers across the end-of-life trajectory. Ethnographic methods will be used to examine the culture of care manifest during formal/informal caregiver interactions, including the complex interplay between the values and beliefs inherent to the care setting;implicit practice theory that influences clinicians'assessment and interpretation of uncertainty;and supportive strategies offered to informal caregivers across different death trajectories. The study will be purposefully extended into a longitudinal study of end-of-life informal family caregiving. We will compare and contrast the informal caregivers'experiences and expressions of uncertainty with the formal care providers'interpretation of the caregivers'status during ongoing clinic visits over the course of one year. The findings of this prospective ethnographic study of the caregiving interface will be translated into a theory-guided, research-based assessment and intervention protocol for supporting distressed family caregivers during brief, yet repeated interactions with professional care providers. We then will be prepared to conduct a supportive care clinical trial testing the efficacy and effectiveness of the devised protocol, moving toward our long-term goal of improving the quality of life of end-of-life caregivers.