Associations between man and certain species of cockroaches possibly started as casually as the short-lived association that Beebe (1953) observed when he discovered three cockroaches in the newly built couch of an orang-utan. Obviously, when man came down from the trees, his fellow travelers found his cave dwellings and other abodes particularly favorable habitats. From such primitive beginnings, domiciliary cockroaches have spread into every kind of structure that man has since devised. We predict that when man develops a suitable vehicle, cockroaches will someday accompany him into space. Yet despite the apparent predilection of certain species of cockroaches for man, man is only incidental to these associations. Only the shelter and food that man unwittingly provides for these unwelcome guests attract cockroaches to him; man's physical presence is unnecessary. Most, if not all, of the common domiciliary cockroaches apparently originated in the Tropics or sub-Tropics from whence they have spread, through normal commercial channels, into most of the inhabited world. At least eight domiciliary cockroaches originated in Africa (Rehn, 1945): _Blatta orientalis_, _Blattella germanica_, _Leucophaea maderae_, _Nauphoeta cinerea_, _Oxyhaloa buprestoides_, _Periplaneta americana_, _P. australasiae_, and _Supella supellectilium_; and, perhaps, _Periplaneta brunnea_ as well; _Neostylopyga rhombifolia_ was probably of Indo-Malayan origin; _Pycnoscelus surinamensis_ was of oriental origin; and _Leurolestes pallidus_ was endemic in the West Indies (Rehn, 1945). Princis (1954a) rejected Africa as the original home of _Blatta orientalis_ and advanced reasons for placing its origin in Central Asia. Several domiciliary species have become well established in temperate zones and some even in the Arctic. Bei-Bienko (1950) listed the following 10 species as sinanthropes in the Palearctic zone: _Blatta lateralis_, _B. orientalis_, _Blattella germanica_, _Leucophaea maderae_, _Periplaneta americana_, _P. australasiae_, _Polyphaga saussurei_, _Pycnoscelus surinamensis_, and _Supella supellectilium_. In the warmer parts of the temperate regions, as in their native Tropics, certain domiciliary species breed outdoors as well as indoors. In the less temperate extensions of their ranges most domiciliary species are nearly always found indoors. In regions with low winter temperatures these cockroaches do not survive in unheated structures; but in heated buildings _Blattella germanica_, for example, has been able to withstand the rigorous climate of Alaska, where it has caused severe infestations (Chamberlin, 1949).