Traces of Her
In my opinion... This is the perfect commute book- it has short chapters, with the rapidly moving plot alternating between the present...
...which is about evenly matched- though my book habit is a little cheaper & easier to indulge on a train in a morning!
I am renowned amongst family & friends for having a book or kindle with me, just in case...I have been reading since an extremely early age - thanks to Mum and the "teach your baby to read" philosophy...