Our local Barnes and Noble has the London AZ but it's the really comprehensive one that may not really be needed by a tourist. I can get an older copy of the Visitors' Atlas and Guide by the same company (1999 edition) at a nearby used bookstore. OR I can get the AAA London spiral book which has some pretty good maps, it appears. Please advise me as to the one you think might be best for a tourist who will be walking between the major central London sights for a few days.

Until you go, work off maps from the internet (www.viamichelin.com, www.mappy.com) - take some printouts with you if you must, and when you get to London, buy one at a bookstore - the selection will be better, and they will be up to date.

Multimap.co.uk produces a-z type maps.

All you'll realistically need once you get here is the small zone one and two a-z, which are on sale everywhere, not just bookshops.

You could just print off this map

www.tfl.gov.uk/buses/pdfdocs/centlond.pdf

Multimap is the best--you have to use the advance search button. You can also print a rough map using Transport for London Journey Planner.

I actually have a couple of good basic maps with major routes and attractions marked but I had seen several posters recommend getting detailed maps/atlases... maybe that's not really necessary.

Not necessary unless you're looking for particular streets and then your hotel should be able to help. The small London A-Z which covers the central city area (where all the main sights are) is available everywhere e.g. at the bookstalls outside main railway stations or tube stations.