The Space Between Worlds

Stories with doppelganger imposters have a long history, from The Prisoner of Zenda to Double Star to Dread Empire's Fall - and this one is a worthy continuation of that traditional trope.

Those who can muster a suspension of disbelief for the unexplained parallel world-hopping tech will be rewarded with an interesting story of assumed identity with just a hint of du Maurier's Rebecca: who was the dead woman, really, and how can her successor achieve a successful and unsuspected transition as her replacement?

My only quibble with this book is that the main character, although in her late 20s, has a bit of a teenagerish feel. Ultimately, however, the author succeeds at creating a gripping mystery-adventure with a satisfying ending.