Hello, I am a novice to manifolds and higher dimensions. Could you recommend a good introductory book(s) or web sites (besides Wikipedia, of which I am aware ) on the subject of the 3-sphere. My goal is to build intuition about the 3-sphere by starting with simple analogies, examples etc. I am not too familiar with group theory, would like to approach the 3-sphere without group notation, if possible. Thank you!