We'll be looking at them out of order from when they were published simply because from a topic standpoint, that makes more sense. The first of these is "What You Should Know About Law" written by Harry Hibschman which seems to have been published first in 1929.
Hibschman's first commentary is a question: "What is Law?" He answers in saying that
In one way it is a collection of rules regulating and protecting the life, rights and property of the citizen- a mass of principles classified, reduced to order, and made generally binding in a given part of the world through the expressed will and authority of the political entity.
Further, Hibschman says that there are 4 sub-parts in identifying "law":
A Law - a rule of action established or adopted by recognized political authority to enforce justice, to prescribe duty or obligation, and to protect life, rights, and property; a means by which certain social ends are attained.
The Law - the specific rule in effect in a given case.
Law - the aggregate body of rules defined above; but
Law is also used in the sense of principle; of a high standard of right or justice as something natural, unimpeachable, and ever operative; or of a philosophical concept, crystallized in the minds of men as a juridical absolute.
He concludes this portion of his commentary by saying that lawyers have an expression, referring to statute or decisions as "That is the law, but it is not law." This reflects the difference in conceptualization between the Roman law concepts of lex (the statutory body of written law) and jus (the entire body of of all law including natural rights).
In the intervening 80-plus years, the accepted legal definition of "law" has shifted from the high ideals of the early 20th century. Black's Law Dictionary, 8th Edition, (c) 2004, starts with this definition:
Law (1) - The regime that orders human activities and relations through systematic application of the force of politically organized society, or through social pressure, backed by force, in such a society; the legal system.
(2) - The aggregate of legislation, judicial precedents, and accepted legal principles; the body of authoritative grounds of judicial and administrative action; esp., the body of rules, standards and principles that the courts of a particular jurisdiction apply in deciding controversies brought before them.
(3) The set of rules or principles dealing with a specific area of the legal system.
(4) The judicial and administrative process; legal action and proceedings.
(5) A statute.
(6) COMMON LAW (law but not equity).
(7) The legal profession.
My first thoughts on seeing the descriptions side by side is that, in the intervening years, we have lost any discussion of law as a protector of rights. What appears to be gone from the overall discussion of what the law is, as Hibschman puts it, is the concept of the law being a high standard of right or justice as something natural, unimpeachable, and ever operative; or of a philosophical concept, crystallized in the minds of men as a juridical absolute. The current definition of "law" seems to speak only of force and power, but not of the protection of natural rights of the individual or of ordering of society other than through force. While there are then twenty-seven different sub-definitions located under different names, including natural law, divine law, moral law and common law directing the reader to other concepts the overall definition of law seems to be solely organized around authoritarian command.
The closest that the Black's definition gets to addressing the protection of rights by the law is an included note by Richard A Posner from The Problems of Jurisprudence p. 220-21 (1990), where he says:
It will help to distinguish three senses of the word 'law.' The first is law as a distinctive social institution; that is the sense invoked when we ask whether primitive law is really law. The second is law as a collection of sets of propositions - the sets we refer to as antitrust law, the law of torts, the Statute of Frauds, and so on. The third is law as a source of rights, duties, and powers, as in the sentence 'The law forbids the murdering heir to inherit.'
When we fail to have a discussion of the law as a source of protection of rights as well as the creation of duties and powers in the highest level definition of 'law,' we lose something more than a simple conceptual discussion. We lose the idea that the law is to be a protector of life, natural rights and property of the individual. Without providing this protection, the law loses its authority as a natural, unimpeachable, and ever operative method of enforcing justice, and merely becomes a cudgel for the authority of the day to to prescribe duty or obligation upon those subjugated to its power.