Question: How many copies of the books by the author of The Leopard have sold worldwide?

Suanfa tongzong (General Source of Computational Methods) is a mathematical text written by sixteenth century Chinese mathematician Cheng Dawei (1533–1606) and published in the year 1592.  The book contains 595 problems divided into 17 chapters.  The book is essentially general arithmetic for the abacus.  The book was the main source available to scholars concerning mathematics as it developed in China’s tradition.  Six years after the publication of Suanfa Tongzong, Cheng Dawei published another book titled "Suanfa Zuanyao" ("A Compendium of calculating Methods").  About 90% of the content of the new book came from the contents of four chapters of the first book with some rearrangement.  It is said that when Suanfa Tongzong was first published, it sold so many copies that the cost of paper went up and the lucrative sales resulted in unscrupulous people beginning to print pirated copies of the book with many errors.  it was this that forced the author to print an abridged version. <SEP> Jo Nesbø (] ; born 29 March 1960) is a Norwegian writer, musician, former economist and reporter.  As of March 2014 more than 3 million copies of his novels have been sold in Norway, and his work has been translated into over 40 languages, selling 30 million copies worldwide.  Nesbø is primarily known for his crime novels about Inspector Harry Hole, but he is also the main vocalist and songwriter for the Norwegian rock band Di Derre.  In 2007 Nesbø also released his first children's book, "Doktor Proktors Prompepulver" (English translation: "Doctor Proctor's Fart Powder").  The 2011 film "Headhunters" is based on Nesbø's novel "Hodejegerne (The Headhunters)". <SEP>  Its Norwegian title is "Panserhjerte", which does not directly translate to The Leopard; it rather means something along the lines of "armoured heart".  Moreover, "leopard" refers to the stealthy tread of the killer in the book, while "armoured heart" is what Harry Hole himself gains by his experiences.  "Panserhjerte" is also a Norwegian term for Constrictive pericarditis.  "The Leopard" is the eighth novel featuring Nesbø's crime detective, Inspector Harry Hole. The Leopard is a crime novel by Norwegian novelist, Jo Nesbø. <SEP> Think and Grow Rich was written in 1937 by Napoleon Hill, promoted as a personal development and self-improvement book.  Hill writes that he was inspired by a suggestion from business magnate and later-philanthropist Andrew Carnegie.  While the book's title and much of the text concerns increased income, the author insists that the philosophy taught in the book can help people succeed in any line of work, to do and be anything they can imagine.  First published during the Great Depression, at the time of Hill's death in 1970, "Think and Grow Rich" had sold more than 20 million copies, and by 2015 over 100 million copies had been sold worldwide.  It remains the biggest seller of Napoleon Hill's books. " BusinessWeek" magazine's Best-Seller List ranked it the sixth best-selling paperback business book 70 years after it was published.  "Think and Grow Rich" is listed in John C. Maxwell's "A Lifetime "Must Read" Books List."