Hello. I have just written a book (well, almost) that uses 1, 1.1, 1.1.1, 1.1.1.1 style headings, and they're working beautifully thanks to Suzanne Barnhill's document on this topic that I have unfortunately misplaced. I now want to change the top headings, the ones that say, e.g. 1 Introduction, 2 Theory and Previous Findings, etc. to insert the word 'Chapter', e.g. Chapter 1: Introduction, Chapter 2: Theory and Previous Findings, etc.

So my first question is: How can I do that?

But also: How can I do that without all my lower-level headings 'inheriting' the word 'Chapter', e.g. Chapter 1: A Quick Overview when all I want is 1.1 A Quick Overview without the word 'Chapter'?

And: How can I prevent this from being inherited by all future documents, such as articles I want to write with the same 1, 1.1, 1.1.1, 1.1.1.1 headings but without the word 'Chapter' appearing as part of the top-level headings, which only makes sense in books, not articles?