well, once it's out here in the open it isn't going to be much of a surprise
but there are plenty of other book related things you could send like a decorated book light or a book cushion (a cushion with one hard flat side so you rest the soft part on your lap and have a hard surface on the other). Going with the tea theme you could send a tea cozy (oh, with irony, of course
Ooh, also a book clutch (which is a hard cover clutch in the dimensions of a standard trade paperback, typically or in a mass-market paperback size, less typically) so you can toss your book into your "everything" bag without having to worry about damage to the cover.
I could go on. But I won't. These ideas are meant to be surprises after all.