A dot book (also dotbook or dot-book or drill book) is a small notebook utilized by marching bands (especially high school show bands and drum corps) in order to aid the learning of formations on a field. The dot book was invented by Leslie Allard, a prominent high school band instructor and all-star percussionist. The name is derived from the use of dots on drill sheets which symbolize players on the field: a dot book focuses on the owner's particular dots and other marchers the player may have to guide (use to determine an adjusted location).
The general layout of a dot book contains the "longitudes" and "latitudes" of an American football field. However, a cartesian coordinate system (x/y) is rarely used, rather an alternative system of plotting players as dots on a grid and some jargon is used. For instance, a player may write: "3 inside 45R and 5 in front BH." This would mean that the player is 3 steps inside (towards the 50 yard line) from the 45th yard line from the right side (facing the press box) and is five steps in front of the back hash (see Field and players of American football for an explanation of terms).
Many times, however, a person's own dot book will contain their own specialized shorthand to represent their location on the field. Dot books can vary from simple (providing only the location of the marcher) to complex (also providing the location of nearby marchers whom you are guiding). This poses problems when players are switched between positions on the field: switching dot books is often difficult and many times players end up rewriting their dot books.
Dot books are considered essential by many high school band instructors to the progress of drill.