Gerhard (Gary) Istok
The unofficial "LEGO Historian" of the hobby, Gary spent some of his early childhood in Germany (where LEGO has the highest household penetration) and has an extensive collection of early LEGO sets and elements and an encyclopedic knowledge of the early history of the product. He delights in sharing his knowledge with others, and often resolves questions that others have about parts variations, set variations, and other historical topics. A LUGNET search for Gary usually turns up lots of interesting posts.
Gary lives in the metro Detroit Michigan area and has produced a CD that contains a lot of LEGO historical information.