Unlike some other MMORPGs that lock you into a particular skill progression from the moment you create your character, in EVE your character can potentially have any skill in the game at its maximum level. However, a jack-of-all-trades is truly a master of none in EVE -- in order to compete effectively with other players you must specialize in one or a few professions, or groups of related skills. (This is roughly analogous to the notion of a character class in other MMORPGs.)
Your choices during the character creation process determine how your character will be specialized when you start the game. Though nothing is stopping you from switching professions, it is often better to first choose your profession and create your character around that profession. The character creation guide has some sample character creation templates that are pre-specialized for certain professions.
As aforementioned, professions are major concentrations of skills and skill points. The major professions are as follows:
Minor Concentrations Edit
Minor concentrations represent add-on sets of skills for a character specialized in another area. They represent a lower investment of skill points than a full-blown profession -- . Minor concentrations are as follows:
Corporate Management Edit
Hacking and ArchaeologyEdit
The skills in this concentration are used exclusively in COSMOS constellations to open certain containers and get mission-specific information. For more information, see the Hacking and Archaeology guide.
Though a character can specialize mining, you will likely want basic and intermediate mining skills at some point in your career. For more information, see the Mining guide.
The skills in this concentration are used for using scan probes and probe launchers.