OCLC Research has released Single Search: The Quest for the Holy Grail .
Here's an excerpt from the announcement:
This report highlights successful strategies in providing a single point of access to library, archive and museum collections. . . .
To address this desire, OCLC Research facilitated a working group of nine single search implementers through discussions about the opportunities for, and obstacles to, integrating single search access across an institution. Members of this group told their stories, identified issues, and acknowledged similarities and differences in their approaches. This brief report summarizes those discussions and highlights the emerging practices in providing single search access to an institution's collections. The goal of the report is to foster successful single search implementations by sharing the experience of the working group with those who are just beginning to plan single search implementations