The following is reprinted from The Best of The Best of Uncle John's Bathroom Reader.

From Hollywood's earliest days, directors have sought to leave their individual marks on their films. Some have devised small "signatures" that identify a film as their work. Can you spot them?

MAKING THEIR MARK

The French have a word for it: auteur (author). It's the name for a theory of filmmaking - the idea that a film director is like a book's author and is responsible for the film's vision, form, and content. Many director's films are easily recognizable as theirs, based on the themes and style that recur in their movies. But some directors also add small signature touches or in-jokes that - if you recognize them - add to the audience's enjoyment.

FRANK CAPRA
Capra had a pet raven named Jimmy, and he found a place for him in several of his movies, starting with You Can't Take It With You (1938).

In the Christmas classic, It's a Wonderful Life (1946), Jimmy the raven sits on Uncle Billy's desk in the Bailey Building and Loan.

ALFRED HITCHCOCK
Probably the best-known of all director signatures, Hitchcock famously placed himself in many of his films - his unmistakable profile appears briefly in 37 out of 54 of them. To help you out, we've sniffed out Hitchcock sightings in some of his most familiar films.

Psycho: About four minutes into the film, Marion (Janet Leigh) returns to her office. You can glimpse Hitchcock, wearing a cowboy hat, through the window. Don't blink or you'll miss him - he's only on-screen for a few seconds.

Rear Window: About 30 minutes into the film, Hitchcock is winding a clock in the songwriter's apartment.

Dial M for Murder: This one is of Sir Alfred's trickier cameos. Roughly 13 minutes into the film, a class reunion photo is shown. That's him on the left of the picture.

Strangers on a Train: Right at the start of the movie, Hitchcock can be seen boarding the train, carrying a double bass.

Lifeboat: Hitchcock appears briefly as the "before" and "after" pictures in a newspaper ad for weight-loss program. Around the time of this movie's filming, Hitchcock had crash dieted and dropped 100 pounds.

QUENTIN TARANTINO
Tarantino is best known for violent films with a healthy dose of black humor. And there are several signatures to watch for: Each movie contain a "trunk shot," during which the camera is set deep in the trunk of a car so it can capture the actors as they lean in and over it.

Each also has an ad for Red Apple cigarettes (a fictional brand.) Tarantino almost always has one or more of his characters barefoot - it's Uma Thurman in Pulp Fiction and the Kill Bill movies.

MARTIN SCORSESE
Taking a leaf from Alfred Hitchcock's book, Scorsese appears in cameos in almost all his films. Going Hitchcock one better, Scorsese also puts many members of his family in small roles.

Cape Fear: Scorsese's mother plays a customer at the fruit stand.

The Color of Money: Scorsese is walking a dog in the casino scene. The dog was actually his own dog, and received a credit as Dog Walkby.

Goodfellas: Scorsese's mother plays Tommy's mother. The director let her ad-lib her entire scene. His father plays the prisoner who put too many onions in the "gravy" (tomato sauce).

Raging Bull: Scorsese can be seen asking Jack to go onstage. Also in Raging Bull, Scorsese's father is part of a mob at the Copa Nightclub.

Taxi Driver: Scorsese is sitting in the background of the campaign headquarters as Cybill Sphepherd walks in.

The article above is reprinted with permission from The Best of the Best of Uncle John's Bathroom Reader.

The Bathroom Reader Institute handpicked the most eye-opening, rib-tickling, and mind-boggling articles from everything they have written over the last ten years and carefully crammed them into 576 pages of the book.

Since 1988, the Bathroom Reader Institute has published a series of popular books containing irresistible bits of trivia and obscure yet fascinating facts. Check out their website here: Bathroom Reader Institute.