Wrack your mind to see if you know jack about unlock packs in this helpful FAQ. I should have been a rapper.

ArenaNet has posted a helpful FAQ to explain some of the intricacies of Skill Unlock Packs.

Q: So, if my PvE character doesn't automatically learn these skills, what's in it for me?

A: Your Heroes gain immediate access to all skills (Heroes know all skills unlocked on your account, regardless of whether you are using the Heroes in PvP or PvE combat). If you own the full campaign associated with the skill unlock pack, your PvE character can also purchase any of the non-elite skills from any skill trainer from that campaign, or you can use elite and non-elite tomes to learn these skills. This may well give you access to some skills before you would encounter them by playing through the game.

Read the FAQ at the Guild Wars website.