What is the theme in The Poetics of Space by Gaston Bachelard?

Bachelard's underlying theme in "The Poetics of Space" is focused on spaces in which things and people live. However, his point of view is not as an architect, engineer or other builder detailing dimensions but rather as a poet imagining. The poetic images of several poets are used as tool to wake and express the soul of imagining consciousness in daydreaming. For example, Edgar Allan Poe details frightful images and experiences in underground haunts that send chills down a reader's spine. None of these images exist anywhere but in his imagination and the reader's soul. In contrast, a poem describing the grounds of a country estate can set the reader to dreaming of a walk through its gardens.