Since the publication of McREL's "2003 Annual Report," McREL staff members wrote more than 100 published articles in practitioner and peer-reviewed journals describing what they know from four decades of research on effective schools as well as years of practical experience working to help educators raise student performance: that improving schools is both a "science" and an "art." This idea is the common thread running through this unique issue of "Noteworthy Perspectives," which brings together several previously published articles from McREL. The issue opens with Bryan Goodwin and Ceri Dean's pointed "Three School Improvement Mistakes (and How to Avoid Them)." The authors assert that there are three common, yet avoidable, mistakes many schools make when trying to implement their school improvement efforts. Next, a McREL policy brief is offered wherein Laura Lefkowits and Carolyn Woempner describe steps a school board might take to improve the environment (and ultimately the performance) of low-performing, high-needs schools. The issue concludes with reprinted highlights of McREL's research on effective school district leaders as it appeared in "The School Administrator" magazine. Collectively, these articles represent some of McREL's best thinking and research to date on what it takes to improve school performance and student achievement. (Individual articles contain references.)