Across the hyperarid Namib Desert, winds have shaped sand into dunes and sandsheets, regulated moisture and temperature levels, and transported organic material, engendering the evolution of psammophilous (sand-living) plants, animals and microbes. Namib dunes stretch from the Buffelsrivier in the Namaqualand Sandveld, South Africa, across the TsauǁKhaeb National Park and the Namib Sand Sea in Namibia, resuming in the Iona Skeleton Coast Transfrontier Park, up to the Rio Curoca in Angola. In their width, the Namib dunefields and sandsheets straddle the coastal fog belt and desert grasslands near the base of the escarpment, while in their length, they span opposite gradients of winter and summer rainfall. Geophysical characteristics vary between seven biotopes and their different configurations in different dune types: interdunes, dune bases, dune plinths, slipfaces, dune crests, sandsheets and nebkha dunes. For over 15 Ma, winds have driven dunes from south to north, transporting evolving psammophilic xerophiles (desert-adapted). Subterranean dynamics in dunes enable psammophiles to obtain water from moisture-retaining sand. Equally important is the aboveground availability of fog due to elevated dunes intercepting advective fog and trapping radiative fog that recycles moisture. Multiple abilities to harvest fog water with benefits that trickle through the biotic communities make fog a key ecosystem driver in most Namib dunes. Many dune plants cope with mobile sand by outgrowing sand deposition or building nebkhas. To cope with sandblasting, psammophorous plants fix a protective layer of sand grains to leaves and roots while other psammophilous plants shield themselves with a thick epidermis and bark or hairs and nested structures or by temporarily or seasonally withdrawing into the sand. Psammophilous animals have developed specialised methodsto move through and on the sand, construct stable burrows, and apply sand attributes such as communication via microseismic vibrations. The biotic communities and the special traits of their constituents differ between biotopes. The Namib dune ecosystems' structures, processes and functioning fundamentally depend on only a few keystone species of plants. Threats to psammophile communities include off-road driving, infrastructure developments, and climate change effects on the wind regimes that alter the most important characteristics of dune dynamics for psammophiles. Ecological restoration of impacts on dune communities is challenging and requires more research. The existing knowledge of Namib dunes was primarily built up in the Namib Sand Sea. However, increased accessibility of other Namib dunefields offers opportunities to broaden research while continuing to increase knowledge of well-studied systems to shrink vital gaps, such as an improved understanding of the subsurface dynamics of moisture and above-ground dynamics of keystone plants.