There are many different types of spellcasting and spellcasters in Dark Age of Camelot. Primary spellcasters such as Wizards and Sorcerers (in the Realm of Albion) learn spells as they advance in level. Each class has several different types (or "lines") of spells that they receive. For example the Wizard of Albion receives three lines of spells based on the elements of fire, ice and earth. All spellcasters can then specialize in one of their lines, making them more powerful at casting that particular line of spells.
Some Hybrid spellcasters (those who can both cast and melee effectively) will only receive spells when they specialize in their magical line.