Underground has appeal to a wide range of readers because of the unique topic of exploration, which is not addressed in other sources. Technology, scientific theory, urban development, engineering principles, and social history are included in text and illustrations that make the complex understandable. In an orderly and interesting manner, Macaulay leads the reader on a fascinating exploration below city streets, where a vast, hidden system supports the life taking place above ground.
Bedrock, being the deepest level of soil, supports sand, clay, and rock, which must be considered before excavation takes place and a foundation is constructed. A foundation is important because it transfers the weight of the building to the material below. To prevent shifting and movement, the foundation must provide uniformity and stability; this becomes even more important if the ground below the building is unstable. Thoughts about multistory buildings or earthquakes remind the reader of the significance of this principle. The reader gains greater respect for the careful construction of the foundation. The description and diagrams of spread foot construction explain how soil and water are removed, laggings are braced, concrete is poured, and steel reinforcing rods are installed, all of which takes several weeks.
Being able to read and understand diagrams and following directions in a well-organized text will be skills enhanced by Macaulay’s book. Variations between the four major types of foundations for larger buildings will call upon the reader to differentiate, promoting careful observation and critical assessment. Skills found in the real world are similar to the work carried out by the engineers in this book. Orderliness, attention to detail, and the ability to synthesize information are skills inherent in the concepts presented in Underground.
Macaulay prevents this book from becoming a textbook through his style of writing; he is like an informed guide who addresses the reader in a clear, direct, conversational tone, never overwhelming his audience with too much information. The detailed drawings provide perspectives from a variety of angles. This refreshing change of views continually modifies the pace and keeps the reader alert. The desire to look and look again at the detailed drawings rewards the viewer: The workers are accurately portrayed, and the human activity above ground is endlessly interesting, with people and animals shown in lifelike situations.
A sense of humor, one of the trademarks of Macaulay’s books, is revealed in the table of contents, entitled “What to Look for on the Street and Where to Find It in the Book.” These words appear in the form of a billboard on a detailed double-page spread of a teeming city street. In this drawing, objects represent locations in the book where information can be found, indicated by a brown circle and a page number. For example, a phone box on the street indicates page 89; the reader turns to page 89 to find an explanation of the telephone system. A cable filled with thousands of wires shows wires for outgoing messages and for responses. The text explains that an average underground cable contains 5,400 wires, or enough for 2,700 simultaneous conversations. Facts of this sort are engaging and impressive.
Underground helps explain all those colored wires seen in a cable for telephones, why steam escapes from manhole covers, how subway systems work, and how the vast network of systems underground support life above ground. Macaulay enables readers to understand and appreciate this underworld because he has been there. He did the research by actually visiting the subterranean world with his notebook, sketchbook, and camera. He interviewed utility workers, engineers, and architects. He portrayed such diligence in his own research that the reader is spellbound by the unique adventure in the inner depths of a world that one cannot see but that is one of the basic support systems of modern civilization.