This chapter is about ‘space’: empty space, spatial structures, and the process of structuring. We organize empty space by building-up structures and artefacts of our everyday existence. This structuring transforms empty space into something of a desired form (e.g. a balanced room, a visually pleasing scene), function (e.g. easily navigable), and semantic connotation (e.g. of a ‘place’). The chapter is written from the perspective of spatial informatics and addresses space at the scale of everyday human perception and thinking. The core of this chapter is to present the informatics of spatial structure; this is done at three levels: (1) the conception of structural form, as it accrues in the minds of people, and its expression, using spatio-linguistic modalities; (2) the formalization of space, using representational means for spatial abstraction; and (3) the computation of structural forms in a manner that constructively assures, assists, and empowers those who conceive of those forms. The chapter is grounded to reality with respect to a particular class of spatial assistance systems, e.g. for spatial design, where our interpretations of creative and constructive assistance are applicable. We also present case studies in domains such as design creativity for media pre-production, and real-time emergency assistance, though architectural design remains an area of special emphasis throughout the chapter.