Who is Mr. Vossen in Anne Frank's diary?

In the early printings of the diary he is called "Mr. Vossen" In later printings, all the real names of those involved were used, and his real name was Johannes Voskuijl. He was the father of Bep Voskuijl, one of the helpers, a secretary at the office. He was a skillful carpenter, and built the "swinging bookcase" that hid the entrance to the secret annex.