"... Four or so of them ordered PIHKAL.... They all got delivered, except for one. The last guy had a knock on his door and the rest of his order hand delivered

"... Four or so of them ordered PIHKAL.... They all got delivered, except for one. The last guy had a knock on his door and the rest of his order hand delivered by a customs/federal police officer/similar who advised that it probably wasn't smart to be ordering banned books from overseas ..." Interesting. You can sort of understand the correlation between specific recipes for elicit drugs like amphetamines which are dangerous. I'd never thought about classes of information restricted that way. Nuclear physics is another I can think of. Whole slabs of nuclear theoretical physics have been removed from common knowledge. Another, military information of which Paladin Press is well known for. The irony, the information in each of these areas are still mostly actively used, or at least only a locked up "instruction manual" away.