Playwright Shi Hang still gets a thrill when he finds hard-to-find books with provocative titles at street stalls - although the pirate copies are often too flawed to finish.

Some best-sellers are not available at your local bookstore. Wang Jing / China Daily

"If these books had not been excluded from bookstores, how could they distinguish themselves from the other titles on the shelves?" said the 39-year-old celebrity, well-known for his large private book collection.

Despite the authorities' tight grip on book titles and content, some frowned upon books - genuine, not pirate copies - have sneaked quietly into the capital for years.

These inflammatory titles, though seemingly too hot for the authorities to handle have never ceased to find their targeted readers, book dealers said - for bookworms, like moths, the brighter the flame the greater the attraction. Forbidden fruit tastes all the sweeter.

Shi said there is nothing illegal in local residents reading these books. And that looking for publications unloved by the authorities has always aroused great interest among ordinary Chinese.

Other book lovers told METRO the fact that the authorities are sensitive about some books makes them even more interesting to some readers keen to know what the books are about.

Copies of these books are often secured during outbound trips, or mailed back to China through small-size overseas book dealers. However, the books do not always make the journey through customs. Although under current laws and regulations, Chinese customs do not have any "blacklist" of publications.

"Sometimes we get the orders, sometimes we don't, sometimes the books get mailed back," a local book dealer, which gets most of its orders by overseas mail, told METRO.

"The good news for book dealers is that customs do not have a blacklist to check everything. The bad news is that customs do not have a blacklist, so they can reject anything."

However, book dealers want to stay in business and some titles can mean walking a precarious tightrope on the official line.

"Some political sensitive books are unwelcome, but they are not necessarily prohibited. But for some that get on the wrong side of the government, we don't want anything to do with them," one book store owner said, on condition of anonymity.

However, as Shi Hang said, "Taboo books often reflect the true reality of our times."

"From ancient literature classics like the A Dream of the Red Mansion to works by Lu Xun, they have all been forbidden books in some eras of our history."

For those who do not want to pay high prices for rare books, it is sometimes possible to find an electronic copy of what they want online, if they are lucky. But book lovers said the PDF versions of the photocopied book can be low quality and flawed.

Among his own collection Shi singles out three rare books: The Yellow Peril by early twentieth century writer Matthew Phipps Shiel, which criticizes modern China's revolution; a recent book on ethnic issues by Chinese writer Wang Lixiong; and an earlier published book on the late years of former premier Zhou Enlai.