What scares the scare masters? And after nearly 100 years of horror films, what stand as the best horror films of all time, according to those who make them?

After surveying more than a 100 luminaries from the horror world, the clear, unmistakable winner is...William Friedkin's 1973 masterpiece "The Exorcist."

When we set out over a month ago to survey horror professionals about the greatest films of the genre, it seemed like an easy enough task: send out a few emails, make a few phone calls, and voila! A fun, endlessly-clickable Halloween feature to definitively determine the Top 100 horror movies of all time.

The actual process of compiling it? Not so easy-peasy. The icons of the horror film are a shadowy lot and getting them to set in stone their all time top 10 of the genre took a fair amount of detective work, pleading and horror wrangling. But at the end of the lane, we pulled it off and have put together the absolute ultimate all time ranking of horror films according to those who make them.

The sheer number and caliber of respondents who took part far surpassed our wildest expectations. In all, we received over 100 lists compiled by some of the biggest names in horror: from modern-day Gothic master Guillermo del Toro; to "Hellraiser" and "Nightbreed" visionary Clive Barker; to musician-turned-auteur Rob Zombie; to horror hostess with the mostess Elvira, Mistress of the Dark (née Cassandra Peterson), whose number one pick is, shall we say, entirely appropriate. Even the entire staff of "micro-budget" power broker Blumhouse put their heads together to contribute their own collective Top 10 to the effort.

In addition to the individual Top 10s (each browsable by name over at the main poll page), we asked 16 luminaries of the genre to weigh in with personal reflections on their No. 1 picks, and in response received thoughtful, funny, and profound assessments from such influential names as "Re-Animator" writer/director Stuart Gordon ("Psycho"), "Candyman" helmer Bernard Rose ("The Devils") and "Jennifer's Body" director Karyn Kusama ("Rosemary's Baby"). Some were succinct, others were profuse and a few were positively overflowing with insights, but each provided us with a fascinating glimpse of the impact their respective top choices had on the thrust of their artistic lives.

So what came out on top after all the votes were tabulated? Let's just say your jaw isn't likely to drop when you lay your eyes on the Top 10, which is composed entirely of agreed-upon classics known even to casual movie fans (though one could certainly nitpick with the order).

Without further ado, here's the Top 10:

1. "The Exorcist" (1973; d. William Friedkin)

2. "The Shining" (1980; d. Stanley Kubrick)

3. "The Texas Chain Saw Massacre" (1974; d. Tobe Hooper)

4. "Rosemary's Baby" (1968; d. Roman Polanski)

5. "Alien" (1979; d. Ridley Scott)

6. "The Thing" (1982; d. John Carpenter)

7. "Halloween" (1978; d. John Carpenter)

8. "Psycho" (1960; d. Alfred Hitchcock)

9. "Night of the Living Dead" (1968; d. George A. Romero)

10. "Jaws" (1975; d. Steven Spielberg)

(Check out the full Top 100 list here.)

As they say, "classics" are classics for a reason. And yet the fun of these lists typically isn't what finishes at the top but rather the little surprises that reveal themselves further down the page. On our list, for example, we were delighted to see such films as Adrian Lyne's still-underrated 1990 head-trip "Jacob's Ladder," Jonathan Glazer's queasily brilliant sci-fi horror "Under the Skin" and Andrzej Zulawski's "Possession" -- arguably the most bizarre portrait of a disintegrating marriage in cinematic history -- crack the Top 100.

On the flip side, it's also interesting to note the films that didn't make the cut. Take, for example, Ealing Studios' 1945 black-and-white spookfest "Dead of Night," a classic anthology once named by none other than Martin Scorsese as one of the 11 scariest horror films of all time. That film not only failed to place in the Top 100 but received nary a mention on any list -- a surprising omission that speaks less to the quality of the film than perhaps to its legacy in the present-day public consciousness. It's also worth noting that it hit smack dab in the middle of a decade that seems all but forgotten in the annals of horror history -- indeed, only two films from that ten-year span appear in the Top 100, and only five received any votes at all. 

Decade-wise, the '70s and '80s unsurprisingly finished neck and neck in the competition for most titles in the Top 100 (21 and 23 films, respectively), with the undercard match being waged between the '60s (14 titles) and the Oughts (15 titles). The '90s, perhaps unfairly pigeonholed as a weak decade for horror, couldn't quite manage to reach the double digits (9 votes), while the '30s coasted on the lasting power of the Universal Monster films to finish with a total of 6 titles in the main list. (You can read more about our scoring methodology here.)

Before we get to the main event, keep in mind that we have supplementary content planned in the leadup to Halloween that will add further depth and perspective to the Top 100, so keep an eye out for more "Ultimate Horror" posts in the days ahead.