My only source of information for "Toltec beliefs" comes from Castaneda's books... but with regard to drug use I could offer the following; when Carlos asks Don Juan why he made him use 'power plants' so many times Don Juan says that its, "... because you're so stupid". (Meaning -insensitive- to the world around you.) The drugs were the fastest way to throw his perceptual focus way out into left field. The fastest way to cause him to examine items of perception of which he was previously unaware. The preferred method of affecting one's consciousness is through meditation and controlled dreaming practices. Drugs are a double-edged sword, they might sever the ties that bind quickly but they are just as likely to maim the person weilding the sword. For that reason, I would recommend to anyone interested in reading the works of Carlos Castaneda that they skip the first two books entirely and perhaps come back to them after having read all of the rest in the series.