The book is in two parts: Pictorial Keys and Master Pages. The Keys are designed for easy visual comparison of details which look alike, narrowing the identification of a shrub to one of a small group -- the family or genus.

Then, in the Master Pages, the species of the shrub is determined, with similar details placed together to highlight differences within the family group, thus eliminating all other possibilities. The details of laurel blossoms on this plate are an example and are followed in the book by details of laurel fruit, leaves, and bark.

All of the 3,550 photographs were made specifically for use in this book and were taken either in the field or of fresh material carefully selected from the more than 20,000 specimens collected. Wherever possible, details such as leaves, fruit, twigs, etc., appear in actual size; otherwise, similar details are reproduced in the same scale.