AGATHÓN, for its issue n. 4|2018, that will be published in December, promotes the topic "Impermanence between Necessity and Pleasure". Time determines and controls the relationship between architecture and history. Time highlights architecture’s capability of being passed on to posterity, to be inheritance and proof, to become a typical symbol of a specific historical period. Today, the idea of duration must be rethought, having to face typical variables of the contemporary era, and identifying a new temporary and mobile architecture, giving raise to new forms and systems belonging to an architecture we can call Temporary. A modernity that increasingly gives immediate answers to constantly changing situations, characterized by the availability of new materials, components and construction systems making the creation of temporary mobile artifacts more responsive to the needs of work and users. Temporary architectures become the non-places of architecture, giving rise to a new and original research, experimentation and design sector, aiming to the creation of ephemeral built places, in contrast with permanent and enduring ones, belonging to a consolidated and more conventional architecture. This is combined with the long history of impermanence and ephemeral in architecture and in the arts connected to it and, among other things, meant as an opportunity to celebrate and experiment on projects. Other that an answer to emergency (natural disasters, exoduses resulting from wars or political traumas, etc.), essential necessity that every community must face to be prepare to an unexpected temporary home environment, impermanence can have a key role in architecture, which, with mobile and variable innovative systems, can give functional answer to the solicitation of our senses: tasting, seeing, feeling, touching, smelling. These solicitations simulate the designer’s creativity to search for temporary architectures and respond to needs and requirements that define and characterize the impermanence (assemble, disassemble, set-up, flexibility, transportability, etc.). Another value sustains impermanence, enriching its meaning: pleasure. It is an added value for the creation of temporary buildings that are highly technological or symbolic, where materials and techniques can enhance the building and become, even for a short period, Architecture. The pleasure’s magnitude is linked to the project’s magnitude, which researches its fulfilment, where anthropometry, typological-dimensional requirements and materials merge into the outcome that, in addition to responding to the specific parameters of temporary architecture, also offers suitable solutions to accessibility for all categories of users. AGATHÒN deals with the theme of "Impermanence between Necessity and Pleasure" with the aim of collecting essays and critical reflections, researches and experiments (of processes, products and materials), projects and creations (of architecture, art and design) that might be case studies for innovation, sustainability and social inclusion, describing the two terms, Necessity and Pleasure, in the following uses: emergency, residence and hospitality, health care, events (cultural, recreational, artistic, commemorative, etc.), trade, work, street food, sport, leisure, training, research, production, etc.