I cannot put my own audiobook discs into audiobooks on ipod nano 7th generation. They always go into th music category

If you select those 'tracks' in the Music part of your computer's iTunes library and do 'get-info' (control-I) then you should get a popup with a series of tabs on it. Select the Options tab on that and change their 'Kind' to 'Audiobook' (the popup, and the options on each tab on it, will vary slightly depending upon whether you've selected one track or multiple tracks when doing 'get-info') :

That should move them to the Books part of your library along with your other audiobooks. You can then delete the current 'music versions of them from your iPod and then sync the new 'aubiobook' versions instead.

King Penguin - when I do this they go across but as individual chapters, not together as a book, whihc makes it difficult to know what is what. Is there a way of reorganisaing them so the chpaters move across to books as a whole book? Thanks.

There may be an easier way to do it, but on mine I've named them so that the first 1 or 2 letters of their chapter names are the chapter number e.g. '01 chapter name', '02 chapter name' (that may not be necessary but it makes it easier for me to see where I am when playing it). I've also given them disc numbers - so when selecting the 'tracks' individually via 'get info' the first one has 'disc 1 of n' on its Info tab, the second 'disc 2 of n' etc. Each audiobook then appears as a separate book in the Music app on my devices with the chapters listed and playing sequentially.