Lovely old, hard-cover Horizon Magazines. These were made without advertisements, and have remarkable feature articles with full colour images along with b/w.
Problems: Sept., Nov., and May 1962 (shown right here); January 1961; November 1963 (mild harm to cover); Autumn 1965; Autumn 1967; Spring, Winter months 1968; Springtime, Summer season, Winter season 1969; Springtime, Summertime 1971; Spring season, Summer 1972; Spring, 1976.
$3.00 each or take all 17 problems for $40.00.