Elmer

Single UK edition; there was no simultaneous or near-simultaneous American edition, so the Dobson 1968 is the only first. The census claim is confirmed. The familiar 1989 Andersen Press Elmer is a re-drawn and slightly shortened re-issue — pictorially and textually a different book, a "first thus" trap, not the first edition — and it is the 1989 version that made the character internationally famous, so it is common while the 1968 Dobson is genuinely scarce (Dominic Winter noted it had not seen another first at auction; COPAC records very few UK institutional copies).