In the book Richard Branson: The Inside Story, by Mick Brown, on page
256 (Chapter 9, Litigation and Consolidation) there is the following
paragraph:

The following year, Oldfield underwent Exegesis, the then fashionable
and expensive ‘therapy’ in which people are shouted at and humiliated
in front of a group, and then convinced by ‘brainwashing’ techniques
that they actually feel better for it. Oldfield emerged a new man.
From being a painfully shy, diffident recluse, he suddenly
metamorphosed into a garrulous and sometimes painfully overbearing
extrovert.

Where do I find out more about Exegesis and how does it work?

Hello markabe-ga

Now disbanded,  Exegesis used to be run by ex-actor Robert D’Aubigny

This article on Mike Oldfield has a description of what was involved. 
Basically, people are subjected to drastic treatment, such as being
shouted at, not being allowed to go to the toilet etc, with the goal
of making them realise that they are responsible for everything that
happens in their lives and cannot blame anyone else for it.  They are
encouraged to visualise and then confront their greatest fears and
problems.  http://www.appleonline.net/richardc/oldfield/incantations.html

It seems it did not continue long after Mike Oldfield used it.
“Exegesis received a bad press at the time. "And I think I might have
had something to do with it." Oldfield's proselytising led to the
group being investigated by the press; it was also the subject of a
controversial television play, and closed down shortly afterwards.”
http://tubular.net/articles/98_08c.shtml

As pinkfreud has pointed out, EST is very similar.  Here is a brief
description “As subjects discussed their biggest problems and fears,
the EST trainers would rant and rave and scream at them, insulting
them until the subject went numb and gave up maintaining any pretense
of pride. At this point, as a rebirth of sorts, they could now begin
their road toward building their lives and themselves from scratch.” 
More about EST and its founder, from a critical standpoint, is
available on http://www.badfads.com/pages/activities/est.html

EST was renamed to “The Forum” and now “Landmark”.  The site at
http://www.stelling.nl/simpos/est.htm has a lot of links to sites with
more information about these.  There is a brief history at
http://www.dike.de/SINUSsekteninfo/lec/history/profile.html

Here is a list of articles which appeared in psychiatry journals about
EST
http://www.xs4all.nl/~anco/mental/randr/forsyk.htm

Here is a page by someone who has gone through “The Forum”.  It is
intended to provide background for anyone considering the method.
http://www.usefulweb.demon.co.uk/forum/

This is the web site of Landmark itself, where you can get information
on their courses and materials: http://www.landmark-education.com/

Search strategy: 1. therapy, Exegesis  2. Robert D’Aubigny   3. Erhard
Seminars Training  4 The Forum

Considering it's disbanded, quite a lot of info was found on it and
related movements. And as for you pinkfreud-ga, is there anything you
don't know? You figured out my long-lost TV show, which turned out to
be J.J. Starbucks, and now this!

Well done and thanks to both of you.

Although there seems to be very little on the Web on this precise
subject, I suggest that if you are interested in how such programs
"work," you may want to look up information about Erhardt Seminars
Training, also known as EST, which very much resembles Exegesis.

Exegesis was a controversial "self-actualization" encounter-group
program that emphasized "rebirthing" and utilized techniques that
resemble brainwashing. Whether Exegesis was therapy or cultic abuse is
a question for debate. Like most such movements, it had its
enthusiastic converts. Also like most such movements, it was condemned
and vilified by most of the established psychiatric community.

Thanks for the kind words, markabe-ga.

Regarding whether there is anything I don't know...

I dunno. ;-)