The whole book is like this, covered with marginalia. There are manicules, trefoils, asterisks, notes more and less extensive. It's a seriously used book.
And do you know who used this book so seriously? He inscribed his name right there on the title page:
O rare Ben Jonson! And while Jonson's book when he used it might seem unprepossessing, later owners certainly valued it for its association and house it accordingly, in its own locked box.
There's much more to be said about Jonson and his books but I wanted to get these pictures up before they burned a hole in my pocket. You can find the catalog record for this book here and I'll try to follow this up with a bit more Jonsonia.
(Oh, I suppose many of you got the title of the blog post, but just for clarification's sake: Jonson is buried in Westminster Abbey under a plaque that reads, "O rare Ben Johnson"--and yes, that's how it's spelled on the plaque, even though Jonson didn't spell his name that way.)