This thesis is based on the author's independent scientific thinking on the essence of building intelligence since 1988, for the purpose of establishing and arguing for the Building Intelligence Framework (BIF). Furthermore, it is based on the Intelligent Buildings (IBs) Survey of twelve office buildings in the Helsinki metropolitan area. The survey was done right after the first boom of construction of intelligent buildings was over in Finland. The IBs Survey project was carried out at the Technical Research Centre of Finland VTT, Building Technology, in 1993-1997, in order to study the feasibility of the IB concept and its existence. The different intelligent building concepts define the intelligent buildings, not the intelligence of the building. This thesis suggests a definition of building intelligence - called the Building Intelligence (BI) - on the premise that human intelligence can imprint intelligence into an inorganic object, such as a building. The implementation of the BI into intelligent buildings is shown by the BIF. The difference between the IB concepts and the BI is clarified. On one hand, the use of the IB concepts for technical purposes, and on the other hand, the scientific aims of the BI and its implementation into the building practise of the IBs - the BIF - is explained. The further the analysis of the empirical data on the IBs Survey proceeds the more evidence of the differences between office buildings, which have been designed using the intelligent building concept as a leading design criterion and the buildings, which have not been designed according to the IB concept criteria are found in terms of the efficacy of these office buildings. This difference is witnessed by the quality evaluation of the end product - i.e. that of the building itself. This quality evaluation is an end-user evaluation, which evaluates the importance of quality of the office building and that of its components to the working efficiency of the evaluator. This is how the evaluation result turns into the efficacy of the office building system, which is composed of its components, i.e. of its subsystems. The result supports the feasibility of the IB concept in office design. The evaluation results from the post-occupancy study correlate with the job description and gender of the office worker. In general, executives evaluate their working environment better than other occupancy groups. The thesis closes with the synthesis of some of the results of the IBs Survey and the theory of the BIF. Finally, the IB elements should form a functional combination, an integrated solution. Simply adding high technology, is not enough. Embedding the building intelligence by merging it into the building is held up as the intelligent solution to the design of a successful intelligent workplace.