A hornbook is a book that serves as primer for study. The hornbook originated in England as long ago as 1450, or earlier. The term has been applied to a few different study materials in different fields. In children's education, in the years before modern educational materials were used, it referred to a leaf or page displaying the alphabet, religious materials, etc., covered with a transparent sheet of horn (or mica) and attached to a frame provided with a handle.
In United States law, a hornbook is a text that gives an overview of a particular area of law. A law hornbook is a type of treatise, usually one volume, which could be a briefer version of a longer, multi-volume treatise. Students in American law schools often use hornbooks as supplements to casebooks.
In childhood education from the mid-16th century to the late 19th century, a hornbook was a primer for children consisting of a sheet containing the letters of the alphabet, mounted on wood, bone, leather, or stone and protected by a thin sheet of transparent horn or mica. Sometimes the sheet was simply pasted against the slice of the horn. The wooden frame often had a handle, and it was usually hung at the child's girdle. The sheet, which was first of vellum and later of paper, contained first a large cross, from which the horn-book was called the Christ Cross Row, or criss-cross row. The alphabet in large and small letters followed. The vowels then formed a line, and their combinations with the consonants were given in a tabular form. The usual Trinitarian formula - "in the name of the Father and of the Sonne and of the Holy Ghost, Amen" - followed, then the Lord's Prayer, the whole concluding with the Roman numerals.