As Phillip R. Burger pointed out in an essay included in the 2005 Bison Books reissue of Richard Lupoff’s Master Of Adventure, 1975 was a particularly good year to be a fan of Tarzan creator Edgar Rice Burroughs.

For one thing, it was the centennial of ERB’s birth, which meant that much attention was being paid to the author and his works. As part of the centennial celebration, Irwin Porges finally published his long-anticipated (and definitive) ERB biography, Edgar Rice Burroughs: The Man Who Created Tarzan. The book was a massive one, with the original 820-page hardback edition measuring two inches thick and big enough to break the reader’s foot should he happen to drop it. (Ballantine Books later released a two-volume paperback edition, which is the copy I have; my father bought the original hardcover release, and years later my son Joshua found his own copy of the hardcover edition at a used bookstore during one of our family vacations.)

Also in 1975, Ballantine Books and Ace Books were still enjoying great success with the paperback reissues of Burroughs’ works that were credited with launching this “Burroughs Boom” in the first place roughly a decade earlier. Ballantine had released the latest set of new editions of the Tarzan and Mars books, while Ace was releasing a number of ERB novels - titles such as The Deputy Sheriff Of Comanche County, The Girl From Hollywood and I Am A Barbarian - in paperback for the very first time. While there had been no new Tarzan films in several years, there was talk of plans for a big-budget film based on the most famous of ERB’s great heroes. (That film - Greystoke: The Legend Of Tarzan, Lord Of The Apes - would finally be released in 1984... three years after the WORST Tarzan movie ever released, 1981’s Tarzan The Ape-Man with Bo Derek as Jane and a handful of cameo appearances by some dull clod in a loincloth that I think was supposed to be Tarzan.)

In the midst of all that year’s ERB-related excitement, a film based on one of Burroughs’ non-Tarzan works was released with relatively little fanfare. The American-International Pictures production of The Land That Time Forgot - starring Doug McClure, an actor best known for his television work in such series as The Virginian, Barbary Coast and Search - was made on a modest budget but became a decent enough success in that summer of 1975. The film - about a German U-Boat that finds its way to a remote island inhabited by dinosaurs and prehistoric ancestors to the human race - was actually a far more faithful adaptation of Burroughs’ original story than any of the Tarzan films had ever been up to that point; and despite (or perhaps because of) its crude special effects, the film provided audiences with the kind of good old-fashioned excitement there just wasn’t very much of in that era just before the release of George Lucas’ Star Wars (1977).

The Land That Time Forgot was successful enough, in fact, that its producers decided to follow it up with an adaptation of yet another ERB novel: At The Earth’s Core, the first of Burroughs’ seven-novel series set in the Inner World of Pellucidar. Doug McClure returned to play the novel’s hero, David Innes, while famed British actor Peter Cushing signed on to play Professor Abner Perry, inventor of the drilling machine that brings he and Innes to Pellucidar in the first place. Rounding out the cast (in more ways than one) was Caroline Munro, a British actress of the era who had developed a well-deserved reputation as science fiction cinema's reigning sex symbol.

Although made by the same team that was responsible for The Land That Time Forgot, At The Earth’s Core (released in 1976) was a much different film. Whereas the earlier film took its unusual story line relatively seriously, At The Earth’s Core often seems as though it is being played for laughs. (The film ends with a humorous scene of the Iron Mole erupting up through the ground just outside the White House and almost looks as if it had been filmed as part of a Monty Python sketch.) McClure seems to be having difficulty keeping a straight face much of the time, and Cushing in particular often appears to be deliberately spoofing the scientist character he had played so often in the horror films produced by England’s Hammer Studios. Meanwhile, Munro’s performance as the prehistoric maiden Dia offers sterling evidence as to why her career was far more dependent upon on her physical attributes than on her acting abilities.

The limitations of the film’s budget are more on display than had been the case in The Land That Time Forgot. The Mahars of the film are a a far cry from the hideous creatures depicted in Burroughs’ original novel; they are ridiculous to look at, seeming more suited to an episode of TV’s Sigmund And The Sea Monsters.

But despite its many flaws, At The Earth’s Core proved yet another success for its producers. It went on to be the 18th most profitable British-made film of 1976, and its spirit of adventure and campy speical effects seems over the years to have given it even more of a cult following than the superior Land That Time Forgot. Its success allowed the producers to adapt a third Burroughs novel: The People That Time Forgot, a sequel to the earlier film which cast Patrick Wayne (John Wayne’s son) as an old friend of the McClure character who puts together a rescue expedition. That film was a disappointment all the way around; unlike the first film, the screenwriters pretty much jettisoned ERB’s plot altogether and committed the unforgivable sin (in the minds of Burroughs fans, at least) of allowing McClure’s character to be found and rescued only to die anyway during the climactic battle (the character survived in the original novel).

It didn’t help that The People That Time Forgot was released around the same time as Star Wars; the groundbreaking special effects in Lucas’ masterpiece made those in People seem even more crude and unimaginative by comparison than they might have otherwise.

The People That Time Forgot was jeered by ERB fans who had enjoyed the original film, putting an end to the series. The producers and McClure reunited one last time for a non-ERB film, Warlords Of Atlantis, which many fans nonetheless consider part of the series simply because of McClure’s presence and the film’s similar “lost world” storyline. (At one time, in fact, Warlords of Atlantis and At The Earth’s Core were released together as a DVD “double feature” by MGM Home Video.)

Today, The Land That Time Forgot still holds the distinction of being the single most faithful motion picture adaptation of ANY Burroughs novel so far, while The People That Time Forgot is considered (by me, anyway) as perhaps the most disappointing of any ERB adaptations. But At The Earth’s Core is in a field by itself: tolerated by many ERB fans as an earnest but ultimately flawed attempt to bring another of the Master Of Adventure’s great worlds to life, but revered by a certain segment science fiction movie fans (along with such other films of the era as George Pal’s Doc Savage: The Man of Bronze [1975] and Roger Corman’s Battle Beyond The Stars [1980]) as a campy “pure popcorn” B-movie that for all its faults is simply a great deal of fun to watch.

As one reviewer stated: “At the Earth’s Core is well worth turning off your brain and taking a look.” I’ll second that opinion. As someone who has been a fan of Edgar Rice Burroughs since the third grade, but who also enjoys a good piece of mindless entertainment every now and then, At The Earth’s Core is a great deal of fun - and for some of us that’s more than enough.. It may be silly, but what’s so wrong with that?