Early College High Schools are proving to be among the most successful school models to serve diverse populations of students in the 21st Century. ECHS Partnership and the MOU (Memorandum of Understanding) is the first in a three-part series to help administrators understand the benefit of the design and how to implement it, including key questions for both partners. With the institute of higher education (college) and the school district collectively working to help students typically underrepresented in higher education, the outcomes are more than promising. Studies show ECHS high school graduation rates well above 90% and 30% of students earning Associate's Degrees (the other 70% typically have far more college credit than their traditional school counterparts). Based on the authors' collective 15 years experience with ECHS in Texas, this first book in the series, based on Early College High School: An Intentional Design, will offer important information on the partnership and MOU. Other books in the series include Book 2 - ECHS Staffing, Students, and Other Stakeholders; and Book 3 - ECHS Structures and Systems which focuses on academics.