Drawing upon video recordings over two years, teacher interviews, school reports, and field notes, this practitioner research study described and analyzed 16 video excerpts from a music therapy group in a public preschool class serving 14 children with autism, for durations ranging from two to sixteen months. The research centered on three of the children who participated in the music therapy group for the majority of both years: Dylan, Gabriel, and Emily. Three areas of ability--in shared attention, interpersonal interaction, and communication--were explored as crucial and challenging dimensions in the children's development. By synthesizing ideas from autism research literature and my working experience, I posited that children demonstrated shared attention, interaction, and communication through five defining early behaviors: (1) eye gaze; (2) affect/facial expression; (3) body movements/gestures/postures; (4) sound-making through vocal/verbal expression; and (5) sound-making through manipulating objects. In the preschool music therapy sessions, the children's participation took four primary forms: instrument play, body movements/dancing, listening, and vocalizations/verbal communication. One of the phenomena witnessed was peripheral attention, in which children who appeared to be uninvolved in an activity then appropriately answered a question or joined in group movements, revealing that they had been indirectly orienting to the activity and people in the group, through peripheral awareness and ear contact, though their body posture and eye gaze had not initially indicated this. Partial or difficult-to-discern approximations, and idiosyncratic expressions of intention or engagement, often preceded and coexisted with children's emerging steps in verbal/vocal communication and interaction with others. By incorporating picture schedules, augmentative and alternative communication devices, instruments, percussion rhythms, bean bags, parachutes, stretch bands, and other visual, tactile, auditory, and kinesthetic dimensions of music and movement, multi-modal opportunities for shared interaction were introduced. The active participation and collaboration of the classroom teachers--David, Elizabeth, and Rachel--also played a pivotal role in encouraging children's participation in the music therapy group. Session excerpts showed children with autism and adults influencing each other in a shared process of learning and exploring relationships. In coordinated vocal interplay, turn-taking and theme-and-variation exchanges, joint percussion and guitar playing, group dancing and movement sequences, and in reciprocal expressions of emotion, interactions in the preschool music therapy group were mutually developed. Taking inspiration from concepts in parent-child research, psychotherapy, education, and music therapy, I have described these interpersonal exchanges within the music therapy group as moments of meeting and musical attunement. [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.]