There are three types of knowing: I know what I know, I know what I don't know, and I don't know what I don't know. Let's call the objects of these three types of knowing as follows: known knowns, known unknowns, and unknown unknowns.
I often hear some philosophically minded people say rather boastfully that they know that they don't know. But they often don't know what they don't know. ;-) In other words, this second type of knowing is not the highest type of knowing.
Actually, there is even a higher type of knowing than the third type, but I'm sure you already know what it is. ;-) So-called mysticism is one of the prime examples of unknown unknowns, and Chassidus is one important type of Jewish mysticism. And Russian book culture was a personal example of an unknown unknown for me.
Some of you may naturally wonder how they can know what they don't know they don't know. A short answer is that there is no way. Now you know what you don't know about what you don't know you don't know. This is a huge step forward. ;-)
A longer answer is that there are ways, but there is one condition according to my own experience with Chassidus. It's humility. Of course, I'm not bragging about my own humility. ;-) Humility is often brought to us through turmoil in life, which in turn shatters our ego - the antagonist of humility. This is also why it's often said that a broken heart is the best preparation for learning Chassidus. But please don't get me wrong. I don't want you to suffer!
Humility makes our inner vessel empty and allows wisdom to enter without obstacle, as rainwater penetrates unpaved ground.
When even one unknown unknown of yours becomes a known unknown, and then slowly shifts toward a known known, you naturally feel like sharing it with others - especially those who are dear to you or those whom you think will benefit from it.
Then you encounter a formidable wall: you can't explain conceptually to someone who still doesn't know what they don't know, and convince them to learn it - not necessarily from you, but in general.
Recently, I've suddenly and finally realized with great clarity one of the main reasons why I've had such difficulty finding students for my courses in Jewish life wisdom based on Chassidus. I've even paid a fortune to two business coaches to get over this obstacle. But I now see clearly why they haven't been able to help me: they only know how to turn known unknowns into known unknowns, but they are helpless when it comes to turning unknown unknowns into known unknowns - which is the prerequisite for many people to take action.
I don't know how successful I've been in this attempt to explain what cannot be fully explained conceptually in language. I have to confess that I've reached my limit. ;-)