The phrase "Siteless: 1001 Building Forms PDF" refers to a highly influential and digitally circulating version of a seminal architectural reference work. To understand its significance, the title breaks down into three key parts: (the concept), 1001 Building Forms (the content), and PDF (the format).

The heart of the work is a visual encyclopedia of 1,001 architectural forms. These are not blueprints or detailed plans; they are —simple, clean, and often playful line sketches of imaginary building masses.