In 1928, the full Oxford English Dictionary was republished in 10 bound volumes.
The edition completed the first publication of what was originally titled A New English Dictionary on Historical Principles. The dictionary had been issued in alphabetic fascicles over several decades, beginning with A and B in 1888. The final fascicle, covering V to Z, appeared in 1928, allowing the complete work to be bound as 10 volumes.
The 1928 publication should not be confused with later OED formats. In 1933, the dictionary was reissued in 12 volumes under the title The Oxford English Dictionary, together with a one-volume supplement. The second edition, published in 1989, was much larger and occupied 20 volumes.
The OED’s size reflects its historical method: it documents words through dated quotations showing how meanings and usage developed. Shakespeare is the most-quoted writer in the completed first edition, while the Bible is the most-quoted work collectively. Thus, 20 volumes belongs to the 1989 second edition, not the 1928 republication.