The more books you have, the more you'll want because there is always something to discover.
Most of the earlier Norton books are based on Titch Allen's 'Norton Story' which appeared in 'Motorcycle Sport' in 1972-73 with a bit of Commando stuff thrown in.
Steve Wilson's book is good on the Commando years at Norton, Mick Woollett's is very good on Norton history but Commandos aren't really his thing and Roy Bacon's 'Norton Twins Restoration' is very good for period detail shots but can get a bit vague in the text. It's a useful aid to putting everything in the right order though.
Basically, if it has 'Norton' in the title, you have to buy it, even if only to rule it out !
