Is Riesling really a German variety?  Or might it have been imported to the Rhine Valley from Austria?  Where and when did the the first Riesling vine grow?  Is it true that an entire vineyard was planted to Riesling at Johannisberg in 1721?  Where, when and why did the low-alcohol-but-substantially-sweet style widely associated with German Riesling originate?  Is it true that most German Riesling is now made in a dry style?  Are Alsatian Rieslings drier than German Rieslings?  John Haeger talked about these and other questions, addressed in his recent book Riesling Rediscovered on Wednesday 10 August at Cartograph Wines in Healdsburg, his talk sponsored by the Friends of the Sonoma Country Wine Library.  An informal tasting of dry Rieslings followed the talk.