Bringing a book to work is allowed.
In fact, the department I'm in today has a shelf in the back of loaner books.
But bringing a Bill Bryson that you've never read before*?
Not so smart.
Because it's really, really hard to explain to your co-workers and the patients why you're sniffling and snorting and have mirthful tears running down your face other than to say 'Here, read this!'
And then they don't get any work done either.
*The Life and Times of the Thunderbolt Kid (A memoir)