Z4CK is a cyber thriller which includes a gripping story line with an insight into realistic hacker tools and techniques. The main story is about a hacker who creates the ultimate security tool capable of breaching any network security. Other tools such as Nmap, Nessus, Hydra, and Netcat are also put to good use in this novel. The PDF is completely free to download.
You can download it from the following link: https://packetstormsecurity.com/files/download/47841/z4ck-book_final.pdf
Source: https://packetstormsecurity.com/files/47841/z4ck-book_final.pdf.html