Relativity is one of those stories that makes you think about the “what ifs.” You know, what if I left the house 5 minutes earlier…would my day have turned out differently or in the case of Ruby, what if her mother had survived the car accident she was in…would Ruby’s life have been different? The exploration of the idea that there are other parallel universes where our lives could be entirely different or even strangely similar based on the choices we make is interesting to me. I enjoyed this book and found the story to be engaging. Ruby has been dragged from California to Ohio by her father. Since he met and married Willow, Ruby has been forced to make some major changes in her life. Namely, move away from everything that is familiar including her best friend (who she wishes were more) George. Additionally, she now has a step-mother and step-sister. There were times where I truly felt bad for the situation. The sense I got was that although her father did love her, he was absorbed by his work and really left Ruby to her own devices. In all honesty, it made me a bit angry on her behalf. While wandering the corn fields, Ruby comes across a tree that has, for some reason, drawn her attention from the house. When she gets closer, she realizes there is something different about the tree and ultimately finds out it is actually something that will transport her to these other parallel universes which she definitely wants to explore. With the draw of potentially finding the perfect world – the one where her mother survived, George is more than just a friend, and everything else has fallen into place - Ruby jumps into the tree to begin her exploration.I won’t go into the detail and history behind how the tree came to be but what happens is Ruby is propelled into these other universes where things are completely different and she needs to determine what is really important. Her choice not only impacts her but she is forced to look at how what she does in each of the universes impacts those around her. She does finally get to a world where her mother is alive and she gets to experience what it would be like to have her be there for her and Ruby doesn't really want to let it go. Overall I thought this book was well done but there is definitely a science/math slant to it. Ruby loves both of these things and Bishara definitely doesn't shy away from bringing up either of these items. It was completely over my head but I don’t think it hurt the story in any way as it brings some credibility to idea that this type of wormhole could potentially exist. Definitely check this one out if you enjoy a story that has some science, some action, a little bit of romance, and the opportunity to explore the unknown. The main character is a likable heroine who needs to decide what is most important to her and in the end, her experience pushes her to make some decisions in her life that she otherwise might not have made.