While a great deal has been written about the complexities of engagement for learners without severe disabilities, there is less for students with severe disabilities. Engagement as a complex construct, consisting of behavioral, cognitive, and emotional components (Finn & Zimmer, 2012; Fredricks, Blumenfeld, & Paris, 2004; Skinner & Pitzer, 2012) must be addressed as conversations continue to grow around instructional practices for these learners. Traditionally, in the literature on students with severe disabilities engagement has been defined in behavioral terms. Thus, the purpose of this study was to examine the perceptions of the experts in the field of severe disabilities on the phenomenon of engagement. Research question guiding this study was the following: How do the experts in the field of severe disabilities conceptualize cognitive and emotional engagement of students with severe disabilities? The qualitative data for the study included verbatim transcripts from 23 semi-structured interviews with the experts in the field of severe disabilities. This study was approached from a theoretical perspective of the transcendental phenomenology of Husserl. Textural, structural, and composite descriptions were constructed first on the individual participant level, and then across all participants. The phenomenological analysis resulted in the essence of the phenomenon of engagement. The findings were broken into four major sections: the essence of engaging instructional environment, the essence of cognitive engagement, the essence of emotional engagement, and the essence of broadly conceptualized engagement. The essence of engaging instructional environment was organized into themes of inclusive education, contextual engagement prerequisites, and meaningfulness of instruction. The essence of cognitive engagement was complex and revealed differences in experts' theoretical frameworks. The major themes of cognitive engagement referred to the academic responding, learning outcomes, engagement being more than participation, meaningfulness, and measurement. The essence of emotional engagement was described by the factors that influence emotional engagement, the concepts of expressing emotions beyond language skills, and concerns about defining and measuring emotional engagement. Finally, the essence of broadly conceptualized engagement was described by the examples of experts' experiences and by the concept that measurement of engagement of students with severe disabilities needs to be individualized. The discussion contained a synthesis of the findings and the connections with the extant literature. Implications for future research and practice are discussed. [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.]