The New Improved Standard Dictionary was issued as a small paperback sized hardback. The August 22, 1942 edition of the (Toronto) Globe and Mail has a review on page 9 which praises its "Canadianess" and said that "it is hard to imagine greater value per cent [the book cost 25 cents] than this [dictionary]."
The Modern Standard English Dictionary is also a hardback and, except for the title, is identical to The New Improved.
The "King's English" Self-Pronouncing Pocket Dictionary and Vocabulary Builder is a paperback and is also identical to The New Improved as described in Part I.
Why three versions with different names but identical contents? Collins trying to increase sales I guess.
What is "Canadianess"? The covers state "30,000 words ... using the official standard of spelling taught in Canadian schools". What authority established the "official standard of spelling"? Don't know but this is still an issue - see here.
Who are the editors, J(ohn) M(axey) Parrish and John R(edgwick) Crossland? They were British, not Canadian. In addition to editing other dictionaries such as The Westminster English Dictionary they edited many non-dictionaries such as The Mammoth Book of Thrillers, Ghosts and Mysteries and The Mammoth Wonder Book for Children, all published in the UK. The impression is that they were not professional lexicographers. Begs the question - what is the source for the Canadian dictionary?
Collins is still in the Canadian Dictionary business - Collins.