Thomas H. Davenport and Laurence Prusak - Working Knowledge: How Organizations Manage What They Know

Pros: Revolutionary vision
Cons: Very theoretical; long on ideas, short on actual implementation details

This is perhaps the seminal work on knowledge management. It was published in 1997, just when the whole KM movement was gaining steam, and was one of the first to really lay down the fundamental concepts of what KM tries to accomplish.

If...

Pros: Good intro to the field, good balance of theory and case studies
Cons: Biased toward large organizations

In the fast-shifting landscape of KM systems and technologies, Working Knowledge is the perfect touchstone. It's a great introduction and examination of the cultural requirements for effective knowledge management. It's sprinkled with enough case studies...