The title pretty much covers the question.
I think that the index of a book is a good analogy for a non-clustered index, as it demonstrates the extra storage and physical separation properties of a non-clustered index. I also think that the page numbers of a book represent well the physical ordering of data, similar to the structure of data with a clustered index.
However I’m a bit of a newbie to more advanced database theory. Does the analogy for page numbering make sense for a clustered index, or are there any properties of a clustered index where this analogy falls over?