Nearly four years have passed since the release of God Forbid's last album, 2005's post-apocalyptic concept piece Constitution of Treason, and, at the time, the New Jersey natives ranked just beneath bands such as Killswitch Engage, Lamb of God, and Shadows Fall in what was then called (rather generously) the New Wave of American Heavy Metal.

Needless to say, much has changed since then, and the heavy metal scene into which the quintet unleashed its fifth long-player, Earthsblood, in early 2009, had seen, among other things, the replacement of melodic death metal with more brutal deathcore, the unlikely rebirth of thrash, the widespread extinction of emo/screamo, and a general stylistic splintering that left no clear indication about the next dominant trend.

But luckily, God Forbid have never been ones to follow trends as much as their own creative muse wherever it might lead them, so although some of their fans may chafe at the inevitable progression presented on Earthsblood, no one can accuse the band of playing it safe.

Nor is there a simple way to categorize the numerous textures and subgenres contributing to the complex architecture of this new collection of songs: thrash, hardcore, death metal, and non-metal...nothing is really out of bounds.

Any given song -- from the concise three-minute punch of "Shallow" to the nine-minute expanse of the title track -- harbors all kinds of instrumental ingredients, including hard/soft mood swings, bludgeoning riffs (some played on down-tuned seven-strings), clean melodies, syncopated and straight-ahead rhythms, etc.

Likewise the vocals, which vary from clean to growled and largely recite very decent lyrics, too -- something one should never take for granted in metal.

As a result, Earthsblood is not only a challenging and unique-sounding heavy metal album, likely to reveal new secrets with every listen, but in many ways a timeless one as well.

It probably won't sink as quickly or appeal as widely as other, more niche-oriented releases, but watch it crop up on many year-end "best of 2009" lists.