I don't recommend a lot of books, but this one provides the most coherent, insight-rich, mind-reorganizing explanations of the human notion of meaning that I've ever seen. The book came out in 1991, when I was entering high school - I wish someone had turned me on to this book back then!
The only other social science book I recommend as strongly is Daly & Wilson's Homicide, an early (1988) attempt at a rigorous evolutionary biological account of killing among humans.
From Chapter Three, "The Four Needs for Meaning: An Existential Shopping List":
There is thus a need for some firm grounding for moral values. Something has to be capable of justifying other things without needing further justification itself. These "somethings" can be called value bases. A value base serves as a source of value without needing in turn to derive its value from another, external source. A value base is accepted without further justification.
A value base is a sake, in the sense of doing something "for the sake of" it. The hierarchies of justification can be expressed in terms of sakes, which are justified for the sake of yet other things. A value base is a sake in itself. People may speak of doing things for the children's sake, for the sake of honor or love, or for God's sake. These "sakes" are accepted as value bases, for they do not need t import their value from somewhere else. In most religions, for example, God's will is accepted as a value base. The believer may do things for the sake of God's will, and the believer does not ask why anyone should do what God wants. God's will can thus justify and legitimize many other actions (or prohibitions), but it does not need to be justified or legitimized on some other basis.
A value base is thus a very important cultural resource. It can justify a set of rules and prohibitions, and it can endow other actions with positive value. Without value bases, people may not see any reason to act in socially desirable ways. This can create problems, for example, for governments that want to regulate the behavior of citizens but lack the value bases to present these demands as justified. In particular, corrupt governments that have seized power by force and seek to alter the social order have chronic difficulties in providing their citizens with justification. As a result, many such governments have to resort to oppression, police action, and institutionalized terror to force the people to accept their policies. People then support the rulers' policies, not because they regard them as good and right, but because they fear the knock on the door during the night the arrest without warrant, the torture and disappearance. In the long run, governments are more secure and successful if the citizens comply because they believe the policies are just and good and right, rather than out of intimidation. But governments need effective value bases to achieve that security and success.
In an important work on value, Jürgen Habermas argued that modernization tends to destroy many traditional value bases, leaving modern society unable to provide sufficient justifications to to get by. Governments may thus often have problems like the preceding example, which lead to conflict with uncooperative citizens. Individuals experience a decay of values and confusion about the proper behavior. As Habermas argues, value bases are rare and difficult to create so their loss can throw a state into crisis. This problem of modern society is important for understanding how people today struggle to find value in their lives....
A value base provides a guideline for making moral judgments.... Ideologies thus tend to need value bases. Without a strong value base, an ideology loses much of its power and effectiveness, and people will not follow it or use it.
[Meanings of Life, p. 40-41. Emphasis in original; citations omitted.]