{{Muggles' Guide to Harry Potter{{BOOKNAME}}/Beginner Spoiler}}
Transfiguration covers a wide range of spells. At the low end of the scale, the first Transfiguration charm learned by Harry's class is changing a match into a needle; the more complex spells include changing creatures from one species to another. It also includes discussions of [[Muggles' Guide to Harry Potter{{BOOKNAME}}/Magic/Animagus|Animagi]], though we don't see how to become one.
As mentioned,Apparently Transfiguration is a core course, probably for all schools, not just Hogwarts, as we hear Professor McGonagall telling [[Muggles' Guide to Harry Potter{{BOOKNAME}}/Characters/Neville Longbottom|Neville]], in ''Harry Potter and the Goblet of Fire'', not to reveal that he has not yet mastered a simple Switching Spell. We note that this is the only mention of this spell, so we have no indication of how long Neville has been trying to learn it; from McGonagall's tone of exasperation, however, we believe it to be something assigned in an earlier year that Neville was still not able to perform to an acceptable level. McGonagall's concern about this perceived failure of teaching on her part would suggest strongly that Transfiguration, including Switching Spells, is taught at [[Muggles' Guide to Harry Potter{{BOOKNAME}}/Places/Beauxbatons Academy of Magic|Beauxbatons]] and [[Muggles' Guide to Harry Potter{{BOOKNAME}}/Places/Durmstrang Institute|Durmstrang]].
It is mentioned in ''The Tales of Beedle the Bard'' that Professor McGonagall had learned and carried out the Animagus transform as part of her research on Transfiguration. We also learn there that the Animagus transform allows the caster to retain human intelligence. While it is possible, theoretically, to Transfigure yourself into an animal, you would also end up with the animal's intelligence, and would be trapped in the form of that animal until some other wizard returned you to your human shape.
In [[Muggles' Guide to Harry Potter{{BOOKNAME}}/Books/Goblet of Fire/Chapter 26|''Harry Potter and the Goblet of Fire'']], [[Muggles' Guide to Harry Potter{{BOOKNAME}}/Characters/Viktor Krum|Viktor Krum]] uses partial transfiguration to give himself a shark's head so that he can breathe underwater. Clearly this is an exception to the rule above that prevents Transfiguring oneself into an animal. We assume that this is very advanced magic, as it would be necessary to give yourself the shark's face and gills, while keeping your brain human so that you can undo the spell afterwards.
