The notion that information seeking is not always a solitary activity, and that people working in collaboration for information intensive tasks should be studied and supported, has become more prevalent in the recent years than ever before. The field of collaborative information seeking (CIS) is re-emerging, and bringing many researchers and practitioners from various disciplines. This workshop is an effort to gather a small and motivated set of such participants. The workshop will incorporate discussions on theoretical foundations of CIS as well as its applications. It will bring together researchers from both academia and industry, working in the fields of CSCW, CSCL, IR, HCI, and PIM to share their ideas, questions, and opinions on how theories and practices from different domains can be brought together to create a strong and rich path ahead for collaborative information seeking/retrieval/searching as well as collective information synthesis and sense-making.