Another preferred site for showing his expertise is his writing desk, where he is in charge of the content and form. Since the turning point in his expert biography in the mid-1990s, a steady stream of popular science books has been published. He tries to communicate technical knowledge to the public in the purest possible way, although this has not been well received by either book reviewers or editors, who say his books are too technical, too hard to read, or promise more than they actually contain (Goudsmit 19 May 2008; Trouw 17 June 2000 , 1 March 2003 .