In August 2010, the Smithsonian Science Education Center (SSEC) received a grant of more than $25 million from the U.S. Department of Education's Investing in Innovation (i3) program for a five-year study to validate its Leadership Assistance for Science Education Reform (LASER) model in three very diverse regions of the United States: rural North Carolina, northern New Mexico, and the Houston Independent School District (HISD). This summary provides a general overview of key themes and lessons learned from case studies for the LASER i3 implementation, with a focus on a subset of Phase 1 schools. Site visits in these schools were conducted in the Spring of 2013, and again in Spring 2014; data collected, analyzed, and reported were primarily from school administrator and teacher interviews during those site visits. Four to five schools from each region were selected for case study analysis -- a total of 14 Phase 1 sites. Three of these schools were categorized as "nontraditional" because of distinct educational approaches adopted prior to LASER i3. In order to protect the anonymity of interviewed school personnel, schools are referenced throughout this report by pseudonyms (e.g., NM-A; HISD-C). This overview presents key "take-aways" from the case studies -- general themes that describe the case study schools' overall experience with the LASER i3 implementation, as well lessons learned: challenges and successes, addressed by specific schools in the case studies.