The word “collaboration” crops up almost 80 times in the text of The Code Breaker, besides showing up in references and acknowledgements. It’s not merely a matter of semantics; scientific collaboration forms the backbone of most of the important discoveries detailed in the book. Though the book is partly a biography of Jennifer Doudna, it is also an ode to all the scientists who made accomplishments in gene editing possible. Isaacson stresses the point by drawing a line from Yoshizumi Ishino, who first noticed spacer sequences in E. coli, to Francisco Mojica, who discovered these sequences were immune mechanism CRISPRs, to Doudna, whose focused on uncovering how CRISPR works. The line stretches through geographies and generations, as Ishino worked in Japan, Mojica in Spain, and Doudna in Berkeley. It connects Gregor Mendel in the late 1850s to Emmanuelle Charpentier in 2011. Further, there is a clear cause-and-effect chain linking these scientists. If Mojica hadn’t read the works of Ishino, or if Jiankui hadn’t heard about the CCR5 enzyme from George Church, would they have made their discoveries? The line also takes the form of inspiration. Doudna’s scientific outlook was forged by reading James Watson’s The Double Helix, and Charpentier was inspired when she passed by the Pasteur Institute.