It IS a first edition, but it is a fifth impression.

The impression line doesn't start at '1' because your copy is a fifth impression. In a copy of the first impression (what most people refer to as the 'first edition') the line would be 13579108642.

The lowest number in the impression line is the impression of the book it is printed in.

. ------------------------------------------------------------------------------------------------------------------------------------------------------Whomever you may murder, there's no police like Holmes.
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