SUMMARY In summer, in 1988, the MOMA Museum of Modern Art in New York inaugurated an architectural exhibition which was composed of certain works which clearly revealed the concept of Deconstruction in Architecture. The architectural works in this exhibition show the “weariness” of the Traditional Architecture, that is, from the Modern Functionalist to the nostalgic Postmodern. However, such weariness does not only affect the form but very frequently, in Architectural Literature, it is just the reverse of the ideological weariness in other fields of knowledge. The Deconstructive phenomenon seems to be a “reflection moment”, a sort of sliding from the ending of the ideologies to Architecture. Therefore, it can be said that the Architectural Deconstruction would not have been possible without the natural succession of the Postmodernity like a criticism against Modernity. What happens is that the Deconstructive theory, which is postmodern in its genealogy, ends up discrediting even the Postmodernity itself. Thus, if the function and “the spirit of times” were the basis for architectural Modernity and the recovery of the memory and the polyphonic meaning were the same for Postmodernity, we can state then that Deconstruction removes and disqualifies both Modernity and Postmodernity at the same time. Any original or primary category on which a structure of knowledge can be reliably based is considered as intentional and pollutant. Together with this situation of criticism and destruction of the traditional criteria of rationality, it is observed, as well as in Literature, the impossibility of achiving a signifier ( the vehicle ) which refers unanimously and purely to a signified ( the meaning ). There is no possibilty in finding the perfect signifier. A signifier always refers to a different signifier and then to another one in an endless process which leads us to doubt about the true meanings of things and consequently about what things are reallylike. Language itself is “corrupted”, “contaminated” and this contamination makes the decision of communicating ( Architecture is communication) and defining prohibitive. Nothing can be preached without falling into error. Beauty, truth and goodness end up dispersing and finally disappearing. Reality as a nucleus bursts into infinite fragments. Therefore, knowledge becomes fragmentary and ontology is so but without any rule: this is the novelty. Architecture does not remain apart this situation. In it, there are infinite original categories of which the most remarkable ones are those once defined by Vitruvio: utilitas, firmitas and venustas. These attributes have always been present in architectural history and their interpretation and consideration have gone over history with more or less intensity. However, from the moment in which reason itself is disqualified to define, as it will be seen in the criticism against Postmodernity, architectural categories and attributes do not only lose density but they will also become the objective of destruction, that is, deconstrucion. Utility, goodness, beauty, functionality and firmness are not a prioris determing factors in Architecture. In any case, these will be determinant if the architect wishes so. The only original or primary aspect in the Deconstructive phenomenon is that there is nothing definitive, ultimate; everything is unstable, provisional. The resources used by Architecture in this respect will be confusion, formalism and consequently just a game. The deconstructive Architecture is only a game of forms which will represent the reverse of structuralism, functionalism and familiarity, in other words, against firmitas, utilitas and venustas. Deconstructive architects allude very frequently the Poststructuralism. Even , Literature refers to Structuralism in a confused way concerning both philosophical tendencies. Structuralist is Aldo Rossi. Poststructuralist is Bernard Tschmi. Thus, in order to make clear what Deconstructive Architecture aims to show a philosophical search has been necessary from the beginning, in which the reason itself and the position of reality are transformed. The beginning is presumably found in Descartes and the Age of Enlightenment. From that time, beauty and even reality are not found in objects anymore but in subjects and this fact begins a process of wilfulness which will reach modern times. This involves the linking of the ideological movements, which have gone through History from Modernity, to the architectural reality and we will notice that in the case of Deconstruction, reflection is just lineal with respect to Poststructuralism, and that Architecture instead of translating, it transfers the Deconstructive ideology into it. The transfer makes the mistake of considering that Architecture is simply speculation when it contains powerful amounts of construction.The Ideological Deconstruction, more than an invulnerable theoretical statute, is in fact an over stimulation in the creative process.Architecture had been never dealt with putting aside reason, even beauty, form,and function and therefore proposing only the flowing, the capriciousness and the chaos as the only way out. Together with this situation of vanishing and removal of any kind of original category in knowledge, there happens simultaneously a phenomenon without which the Architectural Deconstruction had not taken place, that is, the new technologies and the world-wide economy process. The new technologies facilitates entertainment as they release Architecture from unanimous purposes even from the own limits found in the architectural object. To sum up, we can affirm that Deconstruction is a postmodern phenomenon which cancels Modernity and also puts an end to Postmodernity. It entails a conclusive character and the closing of an age: it is the last scream:“ it is the singing of the swan”.