Hindemith's Unterweisung im Tonsatz

[Sallen112]

I need some information about the third volume of this set. I have all three volumes to scan and upload eventually, the first volume: ''Unterweisung im Tonsatz. Theoretischer Teil'' from 1937, The second volume: ''Unterweisung im Tonsatz. Übungsbuch für den zweistimmigen Satz'' from 1939, and the third volume: ''Unterweisung im Tonsatz. Übungsbuch für den dreistimmigen Satz'' from 1970. These are all from the English Version named: ''The Craft of Musical Composition''. The first two volumes are not an issue copyright wise, since they are from his lifetime. What I am actually unsure of since first performance copyright does not apply to books is that the "third" volume only has a copyright date on the volume of 1970 on the volume that I have, but I have found from external research that I have done, there exists an earlier copyright from 1945, believing that to be the first publication for that particular volume. Then this third I have being the second edition. All three of these edition I believe have just Hindemith's writing, possibly except for the third volume, which might have a preface copyrighted still to be removed. Could I then still then upload the third volume even though I believe there is an earlier copyright from 1945, when the 1945 copyright date is not on the actual volume itself, which then would make this volume somewhat PD then in Canada? If the 1945 claim is false of the third volume, then I can conclude that the 1970 one is first edition then.