Tobacco attorneys will cross examine a Mayo Clinic physician today in Minnesota's trial. Internal memos released yesterday paint a picture of an industry that capitalized on a smoker's craving for nicotine even though tobacco companies knew smoking caused lung cancer 40 years ago. They also show the industry led a campaign to reassure smokers that smoking wasn't harmful. Minnesota public radio's Elizabeth Stawicki reports: The papers reveal how British American Tobacco or batco scientists in the 1950's visited numerous individual researchers in the U-S and Canada to find out what they knew about smoking and cancer. From those meetings BATCO concluded smoking caused lung cancer. That was 1958... 36 years before a group of tobacco company C-E-O's testified before congress that smoking was not addictive and did not cause cancer.