There are a number or people who have lead the development of the field of KM. Feel free to add more.
These include:

• Athur Shelley
• Bob Buckman
• Chris Collison - Blog - Twitter
• Dave Snowden - Narrative, Sense making - Blog - Twitter
• David Gurteen - Knowledge Cafe - Twitter
• Dorothy Leonard
• Etienne Wenger - Communities of Practice - Twitter
• Gary Klein - Naturalistic Decision Making
• Geoff Parcell - Blog - Twitter
• Hubert Saint-Onge
• Ikujiro Nonaka
• Jerry Ash - Twitter
• John Seely Brown - Twitter
• Karl Erik Sveiby
• Karl M. Wiig
• Larry Prusak
• Leif Edvinsson - Intellectual Capital
• Michael Polyani
• Nancy Dixon - Blog
• Nick Milton - Twitter
• Patrick Lambe
• Patti Anklam - Blog - Twitter
• Rob Cross - Social Network Analysis
• Stan Garfield - Twitter
• Tom Davenport - Blog - Twitter
• Tom Young - Twitter
• Verna Allee - Value Networks - Blog - Twitter