What do the memoirs of American presidential candidates Ben Carson and Donald Trump have in common with books that teach Nigerian languages like Igbo, Hausa and Yoruba? The answer is that they're all sold on the streets of Nigeria's commercial capital Lagos.

Ogbonna Osiri imports shipping containers of second-hand books from the United States and Canada to satisfy the demand of readers in Nigeria.

"Some people can stay in my warehouse from morning to night, looking for books," he said. "They can just make out one day, be spending here, looking for books."

At his sidewalk stall in the bustling Lagos Island business district, Solomon Roabiu stocks paperbacks from bestselling authors like Tom Clancy and John Grisham, as well as Nigerian writers like Chinua Achebe.

"The books that sell most, they are all motivational books," he said. "You know the motivational books, people use it, some for their business plan, some other things. People buy a lot."

Used-booksellers compete with long established concerns like CSS Bookshops, which opened its doors in 1869. CSS prints, publishes and sells titles ranging from autobiographies to religious texts to schoolbooks.

But Managing Director Dotun Adeboyega says the biggest threat to his business is not second-hand paperbacks but the counterfeit book trade.

"People do not have the money to buy good books, in fact most of the people buy pirated books," he said. "That is the major problem facing the industry."

According to Adeboyega, counterfeiting is so extensive that fake books are being printed overseas and imported into Nigeria. It's a problem he says the government must crack down on.

What do the memoirs of American presidential candidates Ben Carson and Donald Trump have in common with books that teach Nigerian languages like Igbo, Hausa and Yoruba? The answer is that they're all sold on the streets of Nigeria's commercial capital Lagos.

Ogbonna Osiri imports shipping containers of second-hand books from the United States and Canada to satisfy the demand of readers in Nigeria.

"Some people can stay in my warehouse from morning to night, looking for books," he said. "They can just make out one day, be spending here, looking for books."

At his sidewalk stall in the bustling Lagos Island business district, Solomon Roabiu stocks paperbacks from bestselling authors like Tom Clancy and John Grisham, as well as Nigerian writers like Chinua Achebe.

"The books that sell most, they are all motivational books," he said. "You know the motivational books, people use it, some for their business plan, some other things. People buy a lot."

Used-booksellers compete with long established concerns like CSS Bookshops, which opened its doors in 1869. CSS prints, publishes and sells titles ranging from autobiographies to religious texts to schoolbooks.

But Managing Director Dotun Adeboyega says the biggest threat to his business is not second-hand paperbacks but the counterfeit book trade.

"People do not have the money to buy good books, in fact most of the people buy pirated books," he said. "That is the major problem facing the industry."

According to Adeboyega, counterfeiting is so extensive that fake books are being printed overseas and imported into Nigeria. It's a problem he says the government must crack down on.