Why do magnets with aligned electron spins attract?

[zoner7]

Alright. I don't understand the fundamental quantum basis behind the attraction of two magnets. My book notes that magnets manifest themselves when a material such as iron has unpaired electrons in orbitals that spin in the same direction. If an electron is paired, the electrons will spin in opposite directions and their fields will cancel out. That makes sense. But then it notes that two magnets that have unpaired electrons spinning in the same direction will attract one another. Why...?

Thank you

 

[Delphi51]

I don't know any Quantum, but isn't the explanation just that the magnets are magnets because they have electrons whose B doesn't cancel out? "Spinning in the same direction" means their fields will add, making a magnet.