Development and Implementation of Adaptive Web-Based Systems is not a straightforward and trivial task and requires involvement of many disciplines and research areas. In this dissertation, the issues of complexity in such systems, as well as proposal of a new framework in developing and implementing of Adaptive Web-Based Systems are addressed. The proposed framework is consisted of five layers given as: Data layer, Concept layer, User layer, Adaptation layer and Presentation layer. In data layer, a specific data definition that will match the proposed atomic unit concept has been devised. In concept layer, a complete ontology for generic adaptive web based systems has been developed which supports the atomic unit idea. In user layer, browsing behavior and access pattern of the visitors are analyzed. In this layer, a non invasive methods is utilized in order not to obstruct the user's navigational freedom. In adaptation layer, a more structured approach on developing an effective adaptation algorithm is presented, and in presentation layer, a hybrid technique for adaptive content presentation is proposed consisted of document or units sorting and unit zooming/unzooming.