The book discuss's Pennyroyal's theory that the ancient landfills that had been unearthed by archaeologists were in fact temples of sorts; sacred places (hence the name of the book; Implying that the landfills being filled with 'Rubbish' is incorrect, or even the notion is stupid, hence Rubbish (landfill)? Rubbish (incorrect!)!
The book was a best seller but was taken out of print after Pennyroyal was exposed for fraud. His work was based on little to no evidence and was mostly speculation.