HORNBOOK

n. page containing the alphabet and protected with a translucent piece of horn (formerly used to teach children to read); beginner's textbook, primer (for learning to read)

A hornbook is a book that serves as primer for study. The hornbook originated in England in 1450 (Huey, Edmund Burke). The term has been applied to a few different study materials in different fields. In children's education, in the years before modern education materials were used, it referred to a leaf or page containing the alphabet, religious materials, etc., covered with a sheet of transparent horn and fixed in a frame with a handle. In United States Law, a hornbook is a text that gives an overview of a particular area of law.
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(n.)
The first book for children, or that from which in former times they learned their letters and rudiments; -- so called because a sheet of horn covered the small, thin board of oak, or the slip of paper, on which the alphabet, digits, and often the Lord's Prayer, were written or printed; a primer.
  

(n.)
A book containing the rudiments of any science or branch of knowledge; a manual; a handbook.
  

A book which details a specific area of law that is written by a pre-eminent authority on the subject.

Synonyms and related words:
abecedarium, abecedary, alphabet, alphabet book, and arithmetic, basics, battledore, casebook, elementary education, elements, exercise book, first principles, first steps, gradus, grammar, induction, initiation, introduction, manual, manual of instruction, outlines, primer, principia, principles, propaedeutic, reader, reading, rudiments, schoolbook, speller, spelling book, t, text, workbook, writing