Diseases associated with allergy and asthma are increasing in developed countries, with great consequences to health care costs. Often, these diseases reflect pathologic outcomes of type 2 immunity, and are characterized by infiltration of tissues with Th2 cells and eosinophils, by elevations in serum IgE, and by alterations in epithelial and mucosal biology. These responses did not evolve to cause allergies, and clues to the evolutionary pressure to maintain this type of immune response may exist in the response to intestinal helminths, which cause chronic infestations in all vertebrate species on earth. This meeting will bring together scientists from diverse disciplines to discuss new findings in type 2 immunity that suggest close associations of these responses with tissue homeostasis, mucosal microbiomes, and immune integrity that optimize overall fitness of the organism. The goals of this meeting are as follows: 1) to identify gaps in our understanding of type 2 immunity and facilitate future research advances in the field; 2) to promote the development of novel therapeutic strategies against diseases associated with type 2 immunity; and 3) to encourage cross-disciplinary collaborations and establish an on-going dialogue for future research. Opportunities for interdisciplinary interactions will be significantly enhanced by the concurrent meeting on Pathogenic Processes in Asthma and COPD, which will share a keynote address and two plenary sessions with this meeting.