To quote the author The Registry is the part of Windows 98 that can turn you from a casual computer user to a power user. Well, true. If you insist on playing with the Registry you will either become a power user (from repeatedly having to cure the problems you have created for yourself) or become a gibbering wreck (as a result of the hours of sleep you have lost redoing your work).
The worst thing about the registry is that Microsoft changes it in every 32- bit version of Windows they release. This is, of course, a real money- spinner for 'independent' consultants and a guaranteed source of income for writers of books such as this one. Until Microsoft actually designs a user- friendly way of managing your computer(s) you have a few choices.
Set up your machine the way you generally like it and use a product such as DriveImage to take a copy somewhere safe - restore this about once every six months.
Set up your machine the way you want to use it and never install/remove any software.
Resign yourself to periodically rebuilding your software from scratch.
Spend many hours learning how to repair a damaged registry.
Of course there are a number of tools that allow you to limp along some other way. Personally I believe in a belt and braces approach. I set up my system the way I want it, use DriveImage to take a copy onto a second drive and then try to learn to manage my registry by using a book such as this one. Finally, do not change operating systems more than once every three years (and try to stay a couple of years behind the bleeding edge.)
If you want to try to maintain your Windows 98 Registry you will need this book or one like it, but you will also need one for Windows 95 and for Windows NT 4. Just when you have mastered the latter you will need to start over for Windows NT 5. Whatever you do, never assume that what works for one major release will work for another - it usually will but not always.