This study examined the differential effects of two components of the Interactive Strategies Approach (ISA) professional development program on outcomes related to teacher knowledge, teacher practice, and student reading achievement. The professional development for teachers focused on word solving skill among struggling first grade readers. The study also explored teachers' perceptions of a delivery system for professional development designed, in part, to reduce the need for extended contact between the teachers and the professional development provider. Results from the study indicated that teachers made gains in their knowledge of early literacy instruction and reported changes in their instructional practices that were consistent with their professional development condition -- either Alphabetic Knowledge or Strategic Word Identification. Student gains were also consistent with their teachers' professional development condition. Further, consistent with the major hypothesis of the study, the instructional approach to word solving that emphasized the combined use of code-based and meaning-based strategies (Strategic Word Identification condition) resulted in higher performance on measures of word and text level reading. However, no differences were found between the groups on a measure of general reading that included comprehension. The reading and special education teachers who participated in the study reported that they found the materials to be useful for planning instruction with their struggling first grade readers. Teachers were, in general, positive in their responses to the format of the professional development, which included a one-day workshop followed by three monthly, "no-contact" follow-ups featuring supplementary materials that were delivered to the teachers' schools, to be used by them at their convenience. When rating the different supplementary materials, teachers were generally more positive about video demonstrations and "try it out" activities than they were about student assessments or guides for teacher reflection. While teachers were encouraged to collaborate with peers from their building throughout the professional development period, this collaboration did not happen for many of the teachers. In general, teachers who collaborated with their peers had fewer suggestions for changing the professional development delivery system, while several teachers who did not collaborate suggested additional contact time with the professional development provider.