Dean Corso alternates between long filtered and both short and long non-filtered Lucky Strikes, yet the cigarette package is always the short non-filtered type.
When Balkan and Corso enter the collection area early on in the film we see a building outside the many windows in the collection room. In the building outside the lights start going out one-by-one on one of the floors. But a moment later in the next shot, we see the lights back on.
When Corso and The Girl step into the lift at the hotel where Liana Telfer is staying, The Girl's hair is in a messy ponytail. When they get off the lift it's much neater, in the next shot it's messy again.
When Corso pours drinks for himself and Mrs. Telfer, the glasses are generously filled. When he carries them to Mrs. Telfer a few seconds later, they are somewhat less full.
While arriving at his New York apartment building in a downpour of rain, Corso's hair, overcoat and brown paper tote bags appear to be completely dry when he gets upstairs a minute later.
While showing off his collection to Corso, Fargas presents a
"Dictionaire Infernal" by Jacques Collin de Plancy, which he says is a first edition from 1844. The first edition of this influential encyclopedia on superstition appeared in 1818, but its sixth edition, published in 1863, is prized for its illustrations, including 72 drawings of demons. The copy Fargas holds has a title page that is from the 1863 edition.
The sign outside Balkan's lecture has a typo on it. It says "litterature" instead of "literature".
The Sintra railway station depicted is very romantic but makes no resemblance to the real one. In fact, it is Toledo railway station, built in 1919.
When Corso goes to the New York City Library for research, he pulls a copy of Books in Print from the shelf. All major libraries have used CDs of this reference guide for years. Also, he finds an illustration from the book he is researching. Books in Print never printed an illustration.
When Dean enters the elevator in his apartment building if you look at the elevator buttons on the wall, the lower floor numbers; 1,2,3 etc., are at the top of the list when in reality lower floor numbers are always at the bottom of the elevator button panel.
Incorrectly considered a revealing mistake by some. Toward the end of the movie, Corso closes a car door and a reflection is briefly seen in the driver's side-view mirror. Sometimes mistaken for a crew member, it's actually a reflection of Johnny Depp, seen because the angle of the camera looking into the mirror briefly allows Depp to be visible.
When Liana's bodyguard trips while assaulting Corso by the river, the "rocks" underneath him all shift and slide together. It's clearly a mat.
When Fargas is comparing both books for Corso, he supposedly opens both books to the same page to point out an error in printing. However, in the wide shot, it is clear the books are not both open to the same page. The book on the left has a very evident gap in one of the lines that the book on the right does not.
Obvious stunt double when Corso crosses Bleeker Street en route to the rare bookstore in Manhattan.
When Balkan is struggling on the floor with Liana Telfer, the downward wire which causes the lectern to topple is unavoidably visible.
In the film, the book "The Nine Gates" displays an inverted pentagram on its cover to represent its Satanic content. However, the inverted pentagram only became associated with Satanism and evil in the late 19th century due largely to a work by the French occultist Eliphas Levi. As the books were said to be in their original 17th century Venetian bindings, the appearance of the inverted pentagram is an anachronism.
When Liana Telfer smashes the bottle on Corso's head, the sound of glass breaking comes before the bottle actually makes contact.
When Corso is in the cab he asks the driver to stop at the payphone. The cab driver says, "No problem, sir" but his mouth is visible in the mirror and is clearly not speaking.
The footsteps when Corso is walking up the stairs to meet the old woman are off by about 1/2 second. It comes back in sync shortly after he presses the buzzer.
Upon Corso's first visit to the Ceniza brothers, one of the brothers says "I would never have believed she would part with it. Never." When saying 'never' the second time, his mouth is not moving.
When Corso and The Girl drive off in their "borrowed" red sports car, they are stuck behind a truck for a moment, and the car's brake lights are lit; however, the sound of the car accelerating and upshifting can be heard throughout the shot.
In the first quarter of the movie, when Corso is in the library, he turns to his left and you can see the mic cord beneath his shirt.
When Dean Corso meets Boris Balkan for the first time, a crew member is reflected in the library window.
At 1:50 when a fight breaks out over the book an ornament falls over but the string attached to the ornament in order to make it fall over is clearly visible.
Any time The Girl floats down to save the day, the wires supporting her are very visible in the shots.
As Corso asks the cab driver to wait while he goes to the bookstore, we see a motorcycle drive down Bleeker street. The license plate on the motorcycle are French, but Corso is in New York.
Real collectors and dealers wouldn't handle books worth $1,000,000 without gloves, and they surely wouldn't smoke or drink wine directly over them. Also, a book that old (not to mention the XVIII century Don Quixote volumes he takes at the beginning) would not resist the way Corso keeps chucking it in his bag or the fact everybody seems to be handling around. Furthermore, no dealer in his right mind would try to photocopy a four centuries old book by placing it in a commercial machine face down and pressing it as depicted in the movie: such actions would inflict severe damage to the printing and binding, drastically affecting its worth. Regardless those characters who see the book as a tool rather than a priceless collectible, Corso and the brothers Ceniza are experts in the matter, and would never treat such rare and priceless books that way.
When Corso gets a call from Balkan at his hotel in Portugal, he tells him that some of the engravings in the books are signed "LCF" (this includes Balkan's copy as the book dealing brothers point out to Corso) and Balkan reacts as though this was news to him. Given how obsessed he is with the book and the engravings in particular, him not being aware of this doesn't make any sense.
When Corso describes Liana to Gruber, he says "Fortyish...", however, later on when Corso and The Girl lose track of the Liana's Rolls Royce, staring at the "St. Martin" sign, The Girl says to Corso: "Thirtyish..."
Contrary to some claims real collectors and dealers prefer to handle old books without gloves because they just increase the probability of the pages being torn. They also make flipping pages clumsy.