A common characteristic of most of the traditional search and retrieval systems is that they are oriented towards a generic user, often failing in connecting people with what they are really looking for. In this paper we present P I S A, a Personalized Information Search Assistant, which, rather than relying on the unrealistic assumption that the user will precisely specify what she is really looking for when searching, leverages implicit information about the user’s interests. P I S A is a desktop application which provides the user with a highly personalized information space where she can create, manage and organize folders (similarly to email programs), and manage documents retrieved by the system into her folders to best fit her needs. Furthermore, P I S A offers different mechanisms to search the Web, and the possibility of personalizing result delivery and visualization. P I S A learns user and folder profiles from user’s choices, and uses these profiles to improve retrieval effectiveness in searching by selecting the relevant resources to query and filtering the results accordingly. A working prototype has been also developed, tested and evaluated. Preliminary user evaluation and experimental results are very promising, showing that the personalized search environment P I S A provides considerably increases effectiveness and user satisfaction in the searching process.