Annotating PDF Documents with Diagrams and Sketches   NoteBook makes annotating PDF documents easy.  Once added to a Notebook, you can use the diagramming and sketching features to mark up the document, then print it back out to generate a PDF with the markups.  For example, if you’re a student and your professor hands out class notes in PDF form, you can add the PDF notes to your Notebook and mark up the notes within NoteBook.     Adding a PDF Document for Annotation To add a PDF document for annotation, drop the PDF onto a Notebook.  By default NoteBook asks if you want to annotate it.  When you click yes to annotate, NoteBook creates a Notebook page for each page in the PDF document, and sets the PDF page to be the background of the Notebook page.   Once the PDF pages have been added to the Notebook you can use the diagramming, sketching and other tools to add annotations to the PDF. Choose File → Print and Save as PDF to generate a new PDF document from the Notebook pages that includes the annotations.