Nexus, by Ramez NaamRead about the other books on the list.
In Ramez Naam’s debut trilogy (including Crux and the upcoming Apex), a new drug called Nexus links people together mentally, and a young scientist is drawn into a world of trouble that stretches from academia to shadowy government labs. As Kade Lane works to improve the drug, he finds that there are those who are working to use it to turn people into unwitting killers. Naam works to realistically display the consequences of post-human intelligence, as a new generation comes into the world drastically different than their predecessors.
--Marshal Zeringue