I think you can establish that a book is engrossing if the reader of it is so engrossed in it that she ends up on tram 4 instead of tram 8 at 8.30 am in the morning in Rotterdam and thus has to WALK to work for half an hour. 
Yeah, great going there Lannie 
HA! Ik weet naar welke boekwinkel jij gaat… ik heb deze ook net uit! Leuk is tie he! Dus we hebben nog steeds dezelfde interesses…
Liefs nienke