A systematic study surveys large stone monuments worldwide, assembling observations, engravings, and comparative examples to address their age, construction, and uses. The author critiques speculative antiquarian theories and local generalizations, urging architectural comparison across cultures and careful verification of sources. He focuses on megaliths while setting aside drift, cave finds, and smaller stone structures so as not to confuse the argument. The text evaluates competing interpretations — tombs, temples, or astronomical sites — and advances reasoned propositions and tentative suggestions where evidence is uncertain. Numerous illustrations accompany the arguments and aim to stimulate further research and debate.