Arriving roughly ten years after their first hits compilation, 2002’s Forever Delayed, 2011’s National Treasures: The Complete Singles has another decade to cover so it’s perfectly sensible that the collection spans two discs as it diligently marches through almost every single Manic Street Preachers released during their first 20 years. The absences are the province of trainspotters: anything released on Heavenly Records prior to “Motown Junk,” for instance, along with other stray exclusives and fan club bonuses. What is here is everything from 1991’s “Motown Junk” through 2011’s “Postcards from a Young Man,” with a new cover of The The’s “This Is the Day” added at the end as fan bait. Through these two discs, the band’s highs, tragedies, slumps, and comebacks are all evident, the first disc devoted to 1992’s Generation Terrorists through 1996’s Everything Must Go, the second capturing the band’s evolution into respected rabble-rousers. The second disc has the chart-toppers and Top Ten hits -- as late as 2004 and 2005 the Manics were reaching number two with “The Love of Richard Nixon,” “Empty Souls,” and “Your Love Alone Is Not Enough” -- but it’s the first disc, containing the songs they recorded with Richey Edwards and the music they made immediately after his disappearance, that makes the strongest case for their legacy.