Eczematoid Dermatoses of the hands are becoming increasingly prevalent - due, one suspects in no small measure to the complexity of modern life. When such dermatoses are studied one must of necessity resort to a classification, and the one employed here is clinical and aetiological in type. It has been tested against 1364 cases, and has proved serviceable and sufficiently flexible for the purpose but it cannot be regarded as final or complete, particularly when one is dealing with such a complex biological reaction as that of the skin influenced as it is by so many factors, exogenous and endogenous. The mechanism of production of lesions, the effect of various occupations, prevalence, and recalcitrancy factors, are considered when dealing with each subdivision of the classification. Of these 1364 cases, 122 were selected and studied in detail. In the latter detailed study the origin was traced in many cases to mycotic infection of the feet. This in turn led to the study of immunity, and sensitisation in mycotic infections. Towards this j study,human and animal inoculations were performed and immunobiological investigations were made for the presence of humoral antibodies. In the course of this work I also had the opportunity of observing an epidemic of ringworm infection, and from these observations a great deal of material and information were obtained.