I just finished reading Gary Harpst's book - Six Disciplines For Excellence and I strongly recommend it.
As part of my quest for value add, I've read and participated in many "best practice" methodologies over the years. Unfortnuately most are skewed towards theory, with minimal attention to practice and implementation. Sometimes you feel that the authors are locked into outmoded business practices with approaches and examples that are past their due date.
Gary Harpst is the direct opposite. His Six Disciplines For Excellence delivers an effective way to build and grow a business. The approach is current and I love that it ties technology and systems with strategy. Most importantly this book is about execution. It provides the reader with processes, examples, worksheets that last in the real world.
Even though the book is designed for small business I believe it could funcion well within a mid sized company as well. I'm adding Six Disciplines to the reading materials I provide to each of my clients.