The product description above calls this a "new" collection, but it really is a new collection of two previous trade paperbacks, volumes 1 and 2 of Terra Obscura. It takes place in the universe of Tom Strong, the America's Best Comics hero created by famed comic book writer Alan Moore. Terra Obscura was introduced in issues #11 and #12 of "Tom Strong".
If you are not familiar with Tom Strong, let's stop here. Although Alan Moore is justly famous for such creations as "Watchmen" and his fabled run on "Swamp Thing," I personally think he reached his peak of creativity with the Tom Strong comics. If you haven't read them but you love comics (particularly the comics of the 1950s and 1960s), you really should try them. They are collected in six Tom Strong trade paperbacks that should be available on Amazon. The original Terra Obscura story is reprinted in Vol. 2 (or "Book 2") of Tom Strong.
In that initial story, our hero travels to the other side of the galaxy where he finds a duplicate Earth whose history has mirrored our own for the most part. There's even a counterpart to Tom Strong named Tom Strange. But on this parallel Earth, a giant alien is building an immense engine at the South Pole to turn the Earth into a space ship that can be flown away. Most of the superheroes of this far-off Earth have been captured and suspended in time during the period when Tom Strange--who evaded capture--has run across the galaxy (yes, you read that right) to seek Tom Strong's help.
This led to two mini-series, six issues each, about that parallel Earth and its heroes. So you'll see plenty of Tom Strange, but nothing of Tom Strong and his own supporting characters. Also, these stories are not scripted by Alan Moore, who instead was closely involved in the plotting of the story with the actual scripter (Peter Hogan). As such, the sense of quirky fun that Moore brought to his superhero stories at America's Best Comics is sustained in this collection. Fans of Tom Strong should find much to like here, though these stories aren't as satisfying as the Tom Strong series itself. Still, you could do a lot worse than an Alan Moore-plotted story in the Tom Strong universe.
I'm serious, though: you should read the Tom Strong books first, not just because the original Terra Obscura story will add meaning to the stories in this book but also because Tom Strong is the superior reading experience. After you're up to date on Tom Strong, you'll find much to enjoy in this collection.