Mark "Sparky" Stensaas is a freelance naturalist, photographer and author. But his real job is as buyer and marketing director for Duluth Pack. The idea for this book was spawned when Sparky was naturalist at Gooseberry Falls State Park and asked for the 10,000th time, "Is this an agate?" He is the author of Canoe Country wildlife and Canoe Country Flora. Sparky lives in the Nemadji valley of Carlton County. Rick Kollath started illustrating in nursery school and now owns a graphic design studio in Duluth. His familiarity with rocks dates back to a sordid youth as a rock climber. Rick has taught in Austria and traveled around Europe as a climbing bum. Now he gets thrills riding the big waves on the big lake in his little sea kayak.