By Jan Rocha
BBC, Sao Paulo
Vending machines which sell books instead of soft-drinks have been so successful on the Sao Paulo underground railway system that the idea is also going to be introduced on the Rio de Janeiro Metro.
The machines are the brainchild of a Sao Paulo inventor called Fabio Buononetto who wants to get more Brazilians reading books.
Sao Paulo commuters were surprised to find that some of the vending machines where they used to buy ice-cream and soft-drinks, now offer books.
Sao Paulo commuters are getting into books
Titles include translations of Sherlock Holmes, works by Brazilian best-seller Paulo Coelho and even a dictionary of mathematics - surprisingly, one of the most popular among Sao Paulo Metro passengers.
Other best-sellers include practical vegetarian recipes and the consumer defence code.
Mr Buononetto has spent two-and-a-half years working on his idea of offering "food for the mind" rather than food for the body
He believed that the books - all sold at the same price of about $1.50 - will appeal to people who do not normally buy books, and make reading more accessible.
He seems to be right, because the machines now installed at six Metro stations in Sao Paulo, have been a success and now sell about 250 books a month each.
And in a couple of weeks the book vending machines will begin to appear in the Rio Metro, too.