To access Wireframe Mode in the "Book of Shadows" goto Mordant Street, Queens and head to the top floor. Head inside the only door on the floor and go right. When you round the corner you will notice two odd looking floor panels. Jump over these and a message will appear on the screen saying Cheat Enabled. Now check your inventory and access the Book of Shadows (Note: If this is your first cheat the book will appear in your inventory now.)