Between 1938 and 1973 Star Weekly published (I estimate) 1700 titles as inserts in the Saturday edition of the Toronto Star and other papers. I have identified about 1325 of those titles by 660 different authors.
Here are three from the last five years of the run when many of the titles were published over two or three weeks. All are 12 pages.
April 12, 1969 (part 2) - The Astrid Factor by Douglas Orgill (1922-1984), Peter Davies, 1968.
February 12, 1972 (part 2) - The Freedom Trap by Desmond Bagley (1923-1983), Wm. Collins, 1971. Filmed in 1973 as The Mackintosh Man with Paul Newman.
July 21, 1973 (part 2) - Decked With Flowers by Elizabeth Cadell (1903-1989), Hodder & Stoughton, 1973. Advertised as "First Publication Anywhere". When published as a book the title changed to Deck With Flowers.