There are two types of organizations: those who know they have been hacked and those who don't. Nearly every day there is news about a hacked company, regardless of their size.
On the other hand, independent research firms, such as Gartner; Fortune companies, such as Microsoft and Cisco; respected magazines, such as Forbes; global non-profit organizations, such as ISACA; governments; and recruiters are talking about the cybersecurity skill shortage today, and they estimate that the talent gap is in the millions. There are many organizations and individuals that are passionate about closing this gap. There are also possibly endless resources, although very fragmented, on the internet. You will find many books and videos that have the essentials to get you started in cybersecurity, but none of them provide guidance from A to Z on what beginners need to know, what core technology they need to focus on, why they need to have a mentor, how they can network, which certifications they can take, how they can find the resources they need, and finally, how they can find a job.
Again, none of the resources have very well-known industry experts, or hiring managers' advice and suggestions on what a beginner needs to do.
This beginner's guide explores deep technical content pertaining to cybersecurity; however, it also provides real guidance on how to become a cybersecurity expert.
While this book is called a beginner's guide, it also offers a ton of information for professionals who want to switch their careers to cybersecurity.