This book is part of a series of ASCD publications on differentiating instruction. Each is designed to play a particular role in helping educators think about and develop classrooms that attend to learner needs as they guide learners through a curricular sequence.

How to Differentiate Instruction in Mixed-Ability Classrooms (Tomlinson, 2001) explains the basic framework of differentiation. Such a framework allows teachers to plan in consistent and coherent ways. The Differentiated Classroom: Responding to the Needs of All Learners(Tomlinson, 1999b) elaborates on the framework and describes classroom scenarios in which differentiation is taking place. Fulfilling the Promise of the Differentiated Classroom: Strategies and Tools for Responsive Teaching (Tomlinson, 2003) explores the connection between affect and cognition in teaching and learning. It also provides examples of and tools for developing differentiated classrooms in which teachers link affect and cognition. A fourth book, Leadership for Differentiating Schools and Classrooms (Tomlinson & Allan, 2000), discusses how to use what we know about change in schools with goals of differentiation and seeks to provide guidance for educational leaders who want to be a part of promoting and supporting responsive instruction.

In addition to these books, an ASCD Professional Inquiry Kit called Differentiating Instruction for Mixed-Ability Classrooms (Tomlinson, 1996) guides educators, in an inductive manner, to explore and apply key principles of differentiation. Five video programs, all produced by Leslie Kiernan and ASCD, give progressively expansive images of how differentiation actually looks in the classroom. Differentiating Instruction (1997) shows brief applications of differentiating content, process, and products according to student readiness, interest, and learning profile in primary, elementary, middle, and high school classrooms. It also illustrates a number of instructional strategies used for purposes of differentiating or modifying instruction. A three-video set, At Work in the Differentiated Classroom (2001), shows excerpts from a monthlong unit in a middle school classroom as a means of exploring essential principles of differentiation, examines management in differentiated settings from primary grades through high school, and probes the role of the teacher in a differentiated classroom. A Visit to a Differentiated Classroom(2001) takes viewers through a single day in a multi-age, differentiated elementary classroom. Instructional Strategies for the Differentiated Classroom, Part 1 (2003) and Instructional Strategies for the Differentiated Classroom, Part 2 (2004) illustrate how teachers at varying grade levels and in a variety of subjects use seven instructional strategies to ensure academic success for a wide range of students. Each of these materials attempts to help educators think about the nature of classrooms that are defensibly differentiated and move toward development of such classrooms. Each of the publications plays a different role in the process of reflection, definition, and translation.

This book uses yet another lens to examine differentiation and support its implementation in classrooms. It presents educators with a series of actual curricular units developed by teachers who work hard to differentiate instruction in high school classrooms. The book thus moves from defining and describing differentiation to providing the actual curriculum used to differentiate instruction. It is the third book in the Differentiation in Practice series, joining earlier volumes exploring differentiation in grades K–5 (Tomlinson & Eidson, 2003a) and grades 5–9 (Tomlinson & Eidson, 2003b).

What the Book Is (and Isn't) Intended to Be

As we prepared to write this book and its companions, we had numerous conversations between ourselves, with editors, and with many colleagues in education. Each conversation helped us chart our eventual course. Our primary goal was to provide models of differentiated units of study. We wanted to move beyond episodic descriptions of differentiation to show how it might flow through an entire unit. We also wanted to present units at a range of grades and in a variety of subjects, and elected to do so in grade configurations that are reflective of most schools. In this book, we have included differentiated units in mathematics, science, history, language arts/English, world languages, and art in order to demonstrate how differentiation might look in high school classrooms focused on different disciplines.

And while we have developed the book with a high school focus, our intent is that it be useful to a broader range of teachers than the grade levels and subjects it specifically represents. This is a book designed to teach anyone who wants to learn how to differentiate curriculum how to do so—or how to do so more effectively. To that end, we intend that each of the units be more representative than restrictive. That is, an 11th grade history teacher should be able to look at a 9th grade science unit, see how it works, and use similar principles and formats to develop a differentiated history unit for high school juniors. A technology teacher should be able to study several of the units included in the book and synthesize principles and procedures she finds to guide development of a differentiated unit for 7th graders. In sum, we intend this book to be a vehicle for professional development.

What this book is not intended to be is off-the-shelf curriculum for any classroom. It is not possible to create the “correct” unit, for example, on teaching Shakespeare within a historical context. A teacher in one classroom will conceive that process differently than will teachers in other classrooms or teachers in a different part of the country, in a different type of community, or responsible for a different set of academic standards. In the end, then, we are presenting educators with a learning tool, not a teaching tool. If teachers and other educators can read this book and say, “There's something I can learn here,” then we will have succeeded.

How the Book Is Designed

Because we want the book to be a learning tool for a maximum number of teachers, we have made key decisions about its presentation. First, we decided to begin the book with Part I's primer on differentiation—an essential piece for readers new to the topic and a helpful refresher for those already familiar with it. We also opted to include an extended glossary (page 349), which explains terms and strategies that might not be familiar to all readers. Collecting this information in the back of the book, we thought, was preferable to interrupting the units themselves with “sidebar” explanations.

Part II, the body of the book, is devoted to instructional units. We think it will be helpful to share some of our thinking about the layout and contents of the units, each of which is presented in four parts.

• Unit Introduction. The first component of every unit is the introduction, which includes a prose overview of the unit; a list of standards addressed in the unit; the key concepts and generalizations that help with teacher and student focus; a delineation of what students should know, understand, and be able to do as a result of the unit; and a list of the key instructional strategies used in the unit. Some of the units also make links across units and disciplines and promote connections with students' lives and experiences. Note that because of our desire to make the book a learning tool and not a set of lesson plans, we have listed the subject area for each unit, but not a specific grade level. Similarly, our references to the specific standards around which teachers constructed the units do not include grade-level designations.
• Unit Overview Chart. The second component is an overview chart, designed with three goals in mind: 1) to provide orientation in the form of a “big picture” snapshot of the unit's steps or events; 2) to provide an estimate of the amount of time each step or event requires; and 3) to clarify which portions of the unit apply to the class as a whole and which are differentiated. Note that time designations vary from unit to unit; some are designed for 90-minute blocks and some for 45- or 50-minute periods, reflecting the original work of the teachers.
• Unit Description. The third component is the unit description itself. It appears in the left-hand column of each unit page and gives a step-by-step explanation of what takes place in the classroom during the unit. A starburst symbol (*) in the margins highlights differentiated components. All referenced supporting materials (samples such as worksheets, product assignments, rubrics, and homework handouts) appear at the end of the unit.
• Teacher Commentary. The fourth component is an explanation, in the voice of the teacher (or teachers) who created the unit, of what she was thinking as she planned and presented instruction. For our purposes, this is a particularly valuable element. To listen to the teachers who developed and taught these units is to move well beyond what happens in the classroom and to begin to analyze why teachers make decisions as they do. At one point in the writing and editing process, we thought we should reduce the teacher commentary sections to the fewest possible words; we quickly discovered that when we did so, we lost the magic the book has to offer. We hope you enjoy listening to the teachers as much as we have.

We tried to balance two needs in our editing of the units. First, we wanted to maintain the integrity of each teacher's unit without providing so much nitty-gritty detail as to risk distracting from the larger purpose of the work: the illustration of differentiation practices and principles. Second, we wanted to be sure to have both consistency (of terminology, format, essential philosophy, etc.) and variety (in instructional strategies, use of groups, assessment methods, etc.). The teachers who created the units have approved the changes we made or have helped us see how to make necessary modifications more appropriately.

Also, please note that we have opted to make the units somewhat more generic than specific. As teachers, we sometimes have the habit of looking for exact matches for our classroom needs and jettisoning whatever doesn't match. As authors, we can't eliminate the habit, but we wanted to make it a little harder to exercise. For example, although we have taken great care to list state standards reflected in each unit, we have intentionally not listed the name of the state from which the standards came. (It's amazing how similar standards on the same topic are across states.) We hope to make the point that good differentiation is attentive to standards and other curricular requirements, but we want to help readers avoid the inclination to say, “Oh, these aren't my standards, so this would not work in my classroom.”

Finally, we decided to include solid units rather than “showcase” ones. What's here is more roast beef than Beef Wellington. We wanted to include units that demonstrate coherence, focused instruction, thoughtful engagement of students, and flexibility; we did not want to include units that dazzle the imagination. After all, although it may be fascinating to watch someone tap dance on the ceiling, few of us are inclined to try it ourselves. Hopefully, the units in this book are familiar enough to be approachable, but venture far enough into the unfamiliar to provide challenge for future growth. In this regard, our aim for readers is similar to what we recommend for students: pushing them a little beyond their comfort zones. If all readers feel totally at ease with the units, we've lowered the bar. If we send all readers running, we've set the bar too high. (In the latter instance, some judicious rereading over a period of professional growth just might be worthwhile.)

It may well be that the greatest pleasure of teaching comes from learning. It is our hope that this book—and the Differentiation in Practice series as a whole—will serve as one catalyst for helping teachers become the very best professionals they can be.