I've seen comments around the web that say that Tony Buzan didn't invent mind mapping. What he did, they say, was to take a quite well-known technique (going back many hundreds of years according to some sources), narrowed it down with his ten rules and 'invented' a name, which he then trademarked (but see below for more about the mark).
He then marketed this very successfully through BBC programmes (which is where I first encountered it in the 1970s), books and lecture tours. I had heard of and used spider diagrams long before that, though. The fact that we don't hear much mention of "idea sunbursting", a similar technique apparently, but we do hear about Mind Mapping all the time is a tribute to his marketing skill and proselytizing. And this skill has brought the technique to very many people who benefit from its use today and perhaps would not have paid attention to it if they had seen only black and white spider diagrams.
What does it take to "invent" a technique? Is it to define it narrowly, give it a new name and claim that anything similar that doesn't obey the rules is not the same thing? Maybe. It's a point of view...
If he had tried to patent it, would 'prior art' have made the patent application fail? Maybe. It's a point of view. After all, just what can and cannot be patented has changed (especially in the USA) over recent years, so perhaps the absence of a patent is because it wasn't possible to patent an idea in the 1960s or 70s.
We often read references to historical users of mindmapping-like techniques. The classics are Porphyry of Tyros (3rd c.) Ramón Llull (13th c.), Leonardo da Vinci, Albert Einstein, Pablo Picasso, Paul Klee and Winston Churchill. Now, I'd love to see actual examples done by these great figures. If anyone can help with a link to one, please let me know (Vic at this domain). Some of these are "classic" references because at one time, Buzan mentioned them himself on his website, so others picked them up.
More recent claims for academics in the 1960s, M. Ross Quillian and Dr Allan Collins, as originators would be interesting to illustrate with authetic material, and I shall be searching something out to add here. Should be easier than the historical examples, though I notice that Wikipedia has had "citation needed" against that information for some time (still does in April 2008).
The trademark question is easier to resolve. Often you'll see disclaimers on mind mapping web sites that say something like "Mind Mapping, Mindmap and Mind Map, and are registered trademarks of the Buzan Organization". At one time, that seems to have been the case in the UK and USA for the classes software, educational services and publications. But as Euan commented below, objections were lodged and never successfully challenged, so only one general mark survived and that in just a single class. At the time of writing (April 2008) MIND MAPS is registered to the Buzan Organization under "Organising and conducting courses in personal and intellectual awareness and methods of self-improvement; all included in Class 41". That appears to be it for the general mind map area though the organization has registered specific own-product related marks.
Updated with the latest on trademarks after a check of the USPTO and UKIPO records.
17th April, 2008 With thanks to Euan