The Book of Lies was a fascinating read not just for its page-turning story, but also for the themes it explores.One of the themes is, as the title suggests, lies - in particular, the devastating damage they can cause, no matter how small, off-hand or innocent they seem at the time. But what I found most interesting was its exploration of the truth - and, by extension, history - beautifully demonstrating how subjective it is, and how one person's truth is another's lie. We each experience events in our own unique way, with our own version or interpretation of the truth.This point is emphasised through the use of two different narrators - both 15, both living on the island of Guernsey - only 40 years apart. The first narrator we meet is the precocious, overweight, bookish outsider Cat, who, she tells us, has killed her best friend, the beautiful and totally bitchy Nicolette. In the next chapter we're introduced to Charlie, Cat's uncle, as he describes events on Guernsey 40 years earlier, when he too made a fateful friend and apparently caused a death. The book continues to alternate between Cat's and Charlie's stories, revealing details in such a way as to emphasise the parallels between the two and underscore the precariousness of the truth.The Book of Lies works so well because Horlock interweaves these two stories wonderfully, switching between the voices of an '80s schoolgirl and and WWII survivor with such skill that it's never jarring. While both characters are strong, it was Cat's narration that I most enjoyed - not because she was a particularly likable character (she's downright horrid at times), but because she was so authentic. With her melodramatic emotions, delight in big words, desperation to fit in and awkwardness around the guy she likes, I recognised in Cat girls I knew at high school and, dare I say, even myself (dead best friend notwithstanding). My heart went out to both her and Charlie, and ached as the reality of their situations was slowly revealed. Overall, The Book of Lies was a captivating, quick and enjoyable read.