ABC T-REX acquaints children with the shape and name of each letter of the alphabet, as well as objects that begin with the featured letter. The dinosaur munches only on capital letters, but the uppercase and lowercase version of each letter is presented (in boldface) in the single line of text accompanying each illustration. The final pages offer an alphabetized inventory of "some extra things to look for," which encourages young readers to return to pages to find all the objects on the list.

ABC books exist to present and emphasize the letters of the alphabet, and authors typically sacrifice a cohesive story line to achieve this goal. This is true for ABC T-REX, but there is a uniting theme that helps fuse the actions of the character together.

Many boldly colored objects whose names begin with the featured letter are drawn on each page, and the illustrator has gone to great lengths to tie the objects together in some logical fashion. For example, the letter K depicts the tyrannosaurus in a kitchen wearing a kangaroo-print shirt holding a shish kebab with its tail while pouring ketchup. In the background is a kitten eating kibble, and a kettle on the kitchen stove.

There are many ABC books to choose from. Crockett Johnson's Harold's ABC depicts the beloved character drawing a single picture associated with each letter of the alphabet with his purple crayon. Lois Ehlert's Eating the Alphabet: Fruits and Vegetables From A to Z offers more links between food and letters. Tana Hoban's 26 Letters and 99 Cents is both an ABC book and a counting book.