This book has all the wonderful things I've come to expect from Liane Moriarty's work: an enchanting cast of distinct characters, mild plot twists that nonetheless feel delicious and exciting, a steady thrum of tension throughout that drags me through the pages sometimes even against my will, a surprising and satisfying conclusion, and a fervent wish that the book were about 300 pages longer. Or 500. 
 Here's the interesting part: I didn't even like this one as much as the other two of hers I've read (Three Wishes and The Hypnotist's Love Story). Unlike in those books, it took me a while to get a handle on the characters in The Last Anniversary, and I kept getting slightly confused and having to flip back to remember who a character was and how they were all related (which was slightly difficult since I read it on my Nook). But even so, it was so good that I was compelled to finish it in just a few days. Something about her books just sucks me in. And, it bears mentioning, her writing strikes me exactly right every time and makes me laugh a lot. 
 As for what the plot entails, at its core, it's about motherhood. There are other issues (family, secrets, coming to terms with oneself, romantic love, etc.), but the crux of the story, of the mystery, of the climax, and of the resolution focuses on relationships between mothers and children. It's very touching, but not at all sentimental or sappy. 
 If you haven't read a book by Liane Moriarty (or her sister Jaclyn, for that matter), you are seriously missing out and I recommend that you fix that soon.