Book is simplistic and mostly common sense, but the business practices of these people are unethical in the extreme! I have been charged $180 in four months for subscriptions I neither wanted, asked for or approved! Three debits of $37 in August, September, and October and now a new charge for $69 on November 1st. No email or phone numbers either! How can I dispute this issue with a PO Box?? Stay far away!