This paper presents a flexible mining system built on a multi-tier architecture. The architecture of the system is designed on the Model-View-Controller design pattern. The aim of the paper is to define and validate a process of knowledge discovery, starting from structured and unstructured data, in a distributed and heterogeneous environment by integrating Data and Web Mining techniques. The system is able to provide new added value e-Knowledge services in order to meet the diverse e-Knowledge needs of e-business, by driving the user through the three stages of the knowledge discovery, data preparation, data and web mining and result analysis, in an innovative unique process of workflow that integrates a set of existing tools. Each e-Knowledge service represents the result of an orchestration of reusable building blocks, with well defined tasks, able to interoperate among them. Finally, a case study is shown.