ALPHABETICAL ORDER
Alphabetical order, like spelling and the decimal system, is one of the elementary coding systems of our culture. Learning to alphabetize is a basic requirement of our education. It is also quite hard work, since the arbitrary order of the letters cannot be explained or made rational; in itself the order is meaningless and uninteresting. Only long repetition and practice can condition the mind into knowing automatically that Q follows P and that stationery follows stationary. But once the alphabet has been internalized, programmed into the brain, access to vast collections of information is swift and efficient.
It is obvious that most reference books are impossible without the concept of alphabetical order. There is no other all-purpose system for arranging words or names. For special purposes, the entries can be arranged in taxonomic groups, as in a thesaurus or "Yellow Pages" telephone directory. Such arrangements have certain special values, but the disadvantage is that finding an entry in such a list requires thought. Alphabetical order, having no rational content, requires no thought. Some people, such as lexicographers or telephone information clerks, whose work requires continual acts of alphabetical retrieval in a particular book can often open their book at or near the right page at the first attempt, because they have actually internalized the alphabet to their fingertips. Such virtuosity is unnecessary for most people; but average or fast alphabetizing is a useful skill to acquire.
Alphabetizing gives free-ranging access to a vast file of answers to specific questions about language and culture. Every young human being learning his or her native language is certain to ask innumerable questions of the form "What is a-----?" And in every language innumerable adults give innumerable answers of the form "A------is a kind of . It is small, soft, funny-smelling, and yellow. We sometimes use it for making---------."We saw some last week on the way to your grandmother's." This is the folk prototype of a dictionary definition.

THE ROLE OF THE DICTIONARY
It is sometimes claimed that dictionaries are or should be confined to "defining words, not things." Such a limitation is absurd and impossible. Lexicon is not pure language; the process of learning the vocabulary of one's language is an integral part of learning the contents and world view of one's culture. A lexical item is not defined by linguistic information alone. If either the universal adult or the modern dictionary insisted on giving only "linguistic information" in response to a general question about a word, they would rightly be disregarded by the questioner.
Presumably, in a small preliterate culture people have a good chance of learning a high proportion of all of the words in their language by asking and learning. In a modern, literate, industrialized culture this is no longer true. The English language at least is so large that few if any individuals know or need to know even half of its words. Each individual still learns the grammatical structure and the indispensable core vocabulary of his language by listening, imitating, and asking questions. School enlarges the vocabulary in numerous systematic ways. In school one is exposed to the large vocabulary of creative literature (much of it not in oral or current use) and to the technical vocabularies of numerous special pursuits like mathematics and music. In school also,
one is taught to alphabetize and is introduced to the dictionary. From then on, the dictionary and other alphabetized reference books and lists are a second enlargement of the individual's ability to ask questions.
A dictionary is an attempt to make a useful collection of words and give straightforward and consistent answers to the basic questions that are likely to be asked about them. It includes not only linguistic information (the word is a noun) but also much general and technical information (the thing is small and useful) and even visual information (here is a drawing of it). In this way, it directly continues the ancient and universal question-and-answer routine by which lexicon and culture are learned.
In making this Dictionary, we went to very great trouble to identify the best possible selection of questions to answer and to get accurate information about what the best answers would be. The Dictionary is intended for use in American schools in grades 4 through 8. Accordingly, we tried to find out in an objective way which words are actually encountered by the people in these grades. The language that is spoken by children and their teachers could in theory be examined through an immense program of tape recordings, but a project of such complexity and magnitude must be left to the future. We concentrated on getting really good evidence for the printed language used by the educational system itself, as carried in the huge bulk of materials used in the schools.