It measures about 5 and three-quarters inches by about 4 and an eighth inches, and is only about a quarter inch thick.
It's easier to carry in a pocketbook than a paperback book is. I've carried it in my side pants pocket (women's pants).
I use the slipcase that came with my Aluratek Libre Pro when I'm away from home with it. I wouldn't carry around any ereader unprotected - just seems to be commonsense to me. I've dropped things too many times not to use at least a modicum of protection the electronic doodads I carry around with me.
So far, the screen has managed to stand up to my 2 year old nephew poking at the screen with the stylus (he likes to "draw" a picture every day before his nap using the Handwriting application
).