The proposition that tall buildings are necessary to prevent suburban sprawl is impossible to sustain. They do not necessarily achieve higher densities than mid or low-rise development and in some cases are a less-efficient use of space than alternatives. They have, for the most part, the advantages and disadvantages of other high density buildings. They can be energy-efficient, they can be part of mixed-use schemes and they can encourage the use of public transport where there is spare capacity, but so can other types of high density developments. Tall buildings are more often about power, prestige, status and aesthetics than efficient development. The linked PDF is hosted as a public document by the House of Commons of Parliament in the United Kingdom (parliament.uk).