Apress has made one of their InfoSec books freely available in EBook format here. It isn’t the most up-to-date text, but it does deal with a lot of the ideas, principals45, and issues rather than low-down detailed specifics, meaning it still holds a lot of relevance today (e.g. Social Engineering4), Cryptography, Malware, etc). So if you want an easy starter read into this space that’s free you can’t go wrong with this.