American students are getting a warped view of American history from many textbooks, according to an author and educator who will lecture in Des Moines this week. James Loewen, a sociology professor at the University of Vermont, spent two years at the Smithsonian Institution studying the nation’s most commonly used history textbooks.Loewen says textbooks consistently omit parts of American history and what they do cover is glossy, simplistic and perpetuates social and political biases. Loewen’s latest book, “Lies My Teacher Told Me,” contains dozens of examples of textbook errors, like claiming Christopher Columbus disproved the idea that the earth was flat.No one in Europe at that time thought the earth was flat and Columbus’ crew was not on the brink of revolt in their fear of sailing off the edge. That whole idea came out in an 1830 novel. Loewen says the misinformation in history books “makes us stupid when we think about the past and therefore stupid when we think about the present and the future.”Loewen’s free lecture, “What’s Wrong with History Class,” is slated for eight p-m Thursday at Drake University’s Sheslow Auditorium.