A warm, witty take on sexuality, the difficulties of high school and growing up. 4/5 stars. 
 I read the last 30-40 pages with a smile plastered across my face. This is very good. 
 The titular Simon is our first person narrator and I warmed to him pretty much instantly. He makes a few dubious decisions, but he's basically a good kid trying to do his best. We root for him and want him to be happy. 
 The book's particular world of friends, family and high school reminded me of the film Easy A. If you haven't seen this movie, I recommend it. Emma Stone is marvellous, as always, and Stanley Tucci and Patricia Clarkson turn in hilarious performances as her parents. Anyway, if you have seen the film, this should give you some idea of tone and atmosphere of Simon vs. the Homo Sapiens Agenda. 
 A sympathetic narrator, great characters and a central mystery make Simon vs. the Homo Sapiens Agenda a great read. I guessed Blue's identity half way through but it didn't matter. Mostly because I got to chuckle with glee when I was right - ha! 
 I recommend this for everyone and particularly those who enjoy contemporary YA