user = User.new(:login => "login", :password => "password")
book = Book.new(:title => "title")
page = Page.new(:summary => "summary")
work = lambda {
  book.title = "Foooo"
  book.user = user
  page.book = book
  user.save
  book.save
  page.save
}
ok = SuperTransaction.execute(work)
ok                            #=> true
book.title                    #=> "Foooo"

# the following does not work (would be nice if there was a way to make it work)

user = User.new(:login => "login", :password => "password")
book = Book.new(:title => "title")
page = Page.new(:summary => "summary")
ok = SuperTransaction.execute do
  book.title = "Foooo"
  book.user = user
  page.book = book
  user.save
  book.save
  page.save
end
ok                            #=> true
book.title                    #=> nil