The critically-acclaimed auteur Martin Scorsese directed a number of must-see films before The Irishman. Given how his most recent outing has received intense praise for its meditation on guilt and regret, it's easy to see why Martin Scorsese's name has become synonymous with cinematic gold. Since his debut with 1967's Who's That Knocking At My Door, Scorsese has been a trailblazer in cinema, from his early days at the forefront of New Hollywood to his films throughout the 2010s.

While he's been in the public eye for well over 50 years, Scorsese's opinions on superhero films and their "theme park" qualities put him under public scrutiny in 2019. Simply put, Scorsese doesn't believe that the high-octane blockbusters that the general public have come to love are true cinema (with the possible exception of Todd's Phillips' Scorsese-influenced Joker). While some may disagree, with the body of work that Scorsese has and the history that he's made in the industry, it's easy to see why he would think of film in such a particular way.

Related:  Oscars 2020 Best Picture Nominees, Ranked

His opinions on Marvel movies aside, Scorsese's work is a varied body of different artistic ventures. His films tackle themes of Catholic guilt, religious dogma, criminal activity, family, fatherhood, and greed. Such a unique cinematic style makes for a filmography worthy of acclaim. The following films are director's essential, career-defining projects. These movies are not necessarily his best; however, these five spread across a wide scope of his career, and are perfect examples of the versatility that make Martin Scorsese one of the most important filmmakers in history.

Taxi Driver (1976)

Deniro sits in a taxi in Taxi Driver

"I'll work anytime, anywhere." And so begins a twisted journey into the mind of one of the most troubled and intriguing characters in cinematic history, Travis Bickle. Taxi Driver, which was released in 1976, is widely considered to be one of the greatest films of all-time. It received four nominations at the Academy Awards, including Best Picture, Best Original Score, Best Actor (for De Niro) and Best Supporting Actress (for Jodie Foster). On top of its critical accolades, it also has the pleasure of being an incredibly iconic film, as Taxi Driver's most memorable quotes and scenes are ingrained directly into American pop culture and public consciousness.

But on a deeper level, Taxi Driver is a movie that explores both human psychology and human sociology. Viewers get to witness Travis' declining mental state firsthand, like passengers in the back of his taxi. Audiences watch as the mentally unstable Vietnam veteran succumbs to his obsessions and paranoia, and attempts to become something akin to a martyr or an anti-hero — someone to be remembered. However, the audience also gets to experience firsthand the societal rot that pushes Travis into becoming this way. New York City here is not the shining beacon of American exceptionalism; it's a decaying cesspool of mankind's worst tendencies, and a monument to the rejection of human kindness. Without condoning or justifying Travis' actions, the film understands the circumstances that leads him to them. It's no wonder then, that Taxi Driver would go on to become a major influence for Todd Phillips' grounded character study of The Joker.

The King Of Comedy (1982)

Rupert Pupkin King of Comedy

Speaking of inspirations for Joker, The King of Comedy is another early Scorsese film that the recent DC Comics adaptation borrowed heavily from. Released in 1982, the film is the fifth collaboration between Scorsese and De Niro (who some might call his muse), and can be considered a sister film to Taxi Driver. Aside from sharing a lead actor and a setting of New York City, The King of Comedy also examines the deteriorating mental state of a young man, but this time for a different effect.

Related: Every Martin Scorsese Movie Ranked, Worst To Best

De Niro's Rupert Pupkin, while similarly troubled to Travis Bickle, is less dour and cynical and more narcissistic. A wannabe stand-up comic, Pupkin truly believes comedy is his calling and will do anything for his shot at fame, including harassing and inevitably kidnapping his celebrity inspiration Jerry Langford (played by real life "King of Comedy" Jerry Lewis). While Taxi Driver explores moral decay and society's culpability in the creation of a ticking time bomb, Comedy focuses on celebrity worship and the dissonance between the American public and their on-screen heroes. Pupkin, like so many of those who consume and watch media, believes that he is entitled to Langford's personage and his autonomy as a human being. While a dark comedy at first glance, The King of Comedy takes its time in revealing its true nature. The movie isn't a window into the world of its characters, its a mirror reflecting back at its audience.

Goodfellas (1990)

Martin Scorsese's name is synonymous with the depiction of the Italian-American gangster on-screen, and it's arguably Goodfellas that's responsible for that legacy. Based on the true-crime book Wiseguy by Nicholas Pileggi, Scorsese also wrote the screenplay alongside the author. One of the biggest and most talented ensemble casts ever assembled, the movie stars Ray Liotta as Henry Hill, a young man desperate to be indoctrinated into the underbelly of organized crime, as well as frequent Scorsese collaborators Robert De Niro and Joe Pesci as senior members of the Mafia.

While a frequent criticism of Scorsese's films is that they glamorize the criminal lifestyle, Goodfellas is a direct rebuke of that idea. Because the main character is a former gangster, Scorsese spends time emphasizing the temptations and vices that pulled Hill into the Mafia lifestyle in the first place. However, through Tommy Devito's actions, both Henry Hill and the audience grow to understand the toxicity and brutality that accompanies a lifestyle of criminal activity. As the movie comes to a close, it underscores the age-old adage that serves as a major theme for all of Scorsese's gangster-related films: crime doesn't pay.

Shutter Island (2010)

Leonardo Shutter Island

Jumping forward a whole 20 years, Scorsese ended the decade with a return to a genre that he helped to define with some of his earlier films: the psychological thriller. Shutter Island stars Leonardo DiCaprio (another frequent Scorsese collaborator) as U.S. Marshal Edward "Teddy" Daniels, who's tasked with visiting the Ashecliffe Hospital for the Criminally Insane and investigating the disappearance of a patient named Rachel Solando, who was imprisoned for drowning her three children. Accompanying him is his new partner Chuck Aule, played by the Incredible Hulk himself, Mark Ruffalo.

Related: Best Movie Plot Twists Of The Decade

Shutter Island is a masterclass in how to build genuine tension and thrills without relying on tired genre tropes. Based on a 2003 novel by Dennis Lehane, Scorsese uses the source material to weave an intricate and complicated plot, packed full of jarring and shocking reveals. In the hands of a less capable filmmaker, the movie might have fallen into a convoluted mess, but the film is tethered by the strength of its director, as well as the raw talent of its lead and supporting cast, all of whom channel their A-game in bringing the Ashecliffe Hospital to life in a terrifying fashion.

Hugo (2011)

Hugo gears

A true testament to the versatility of Martin Scorsese's body of work, Hugo is both a visually-stunning coming-of-age film as well as a heartwarming celebration of the medium of film and one of its pioneers. Based on the book The Invention of Hugo Cabret by Brian Selznick, the film adaptation secured eleven Academy Award nominations and won five of them: Best Cinematography, Best Art Direction, Best Sound Mixing, Best Sound Editing, and Best Visual Effects.

Asa Butterfield is Hugo Cabret, a young orphan living alone in the Gare Montparnasse railway station in Paris in the 1930s. Uncovering a mystery revolving his late father, a wind-up automaton, and a heart-shaped key, Hugo takes a grand adventure through Paris as well as the history of cinema, a vehicle through which Scorsese injects a clear amount of passion and childlike-wonder. Hugo at times feels more like the best Spielberg efforts of the 1980s in its epic scale and awe, but at the same time it's exactly the kind of movie that only Martin Scorsese could make: intimate, human, and breathtaking.

More: Every Movie That Inspired Joker's Best Scenes