This dissertation research addresses a gap in the library and information science literature on everyday life information (ELI) needs and experiences of emerging adults with intellectual disabilities (I/DD). Emerging adulthood refers to the period between the late teen years and mid-twenties. Although this is a period of significant change for all young people, for individuals with I/DD this life stage is recognized as one of the most stressful times of life. The challenges experienced by these individuals suggest considerable areas of information need. This case study research explored the ELI needs, practices, and challenges of four emerging adults with I/DD. Employing a participatory research approach, participants played a central role in the inquiry process by offering time, input, and invitations into their daily lives for observation and study. Data collection methods included semi-structured interviews, participant/non-participant observations, artwork, photography, and document review of IEP and PCP reports. Analyses revealed four rich and multifaceted lives led by individuals exhibiting a wide range of both formidable and whimsical ELI needs. Twenty-nine categories of ELI need were identified, including multiple subcategories. All four participants displayed high motivation and great initiative in their ELI practice as information seekers, consumers, producers, managers, and providers. They also employed a wide range of tools, resources, and strategies to their advantage, despite considerable challenges---inherent and imposed. Barriers inhibiting information access were identified under the following categories: intrapersonal, physical, economic, social, and institutional. Results from this study parallel findings from other youth-ELI studies. The need for cognitively accessible information and proactive LIS service was underscored in each case study as a necessary mean toward supporting the developmental processes of emerging adults with I/DD and the development of knowledge, skills, and dispositions for self-actualization and enhanced adult life outcomes. A person-centered, outcomes-oriented model for LIS research and practice is proposed with emphasis on a strengths-based approach that capitalizes on individual capabilities, interests, and life priorities in recognition of the whole person. Five target areas are identified for LIS attention: individual capacity building, social capital, developmental processes, quality of life, and enabling environments. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]