James gleick compares a book to a hammer because both:

What is transmission control protocol/internet protocol (tcp/ip)? software that prevents direct communication between a sending and receiving computer and is used to monitor packets for security reasons a standard that specifies the format of data as well as the rules to be followed during transmission a simple network protocol that allows the transfer of files between two computers on the internet a standard internet protocol that provides the technical foundation for the public internet as well as for large numbers of private networks