He was one of many "correspondents" my father wrote back and forth with early on. As regards his training ideas, they were generally pre-modern training ideas, that is, advice was often to follow a very large and wide group of exercises for one set each, not necessarily to exhaustion or anything. And, Liederman's exercises were just the traditional strand movements of that era.
His ideas morphed over time to follow trends.
We just moved so I don't have my albums out but I have a large photo, the most famous one of Liederman, with a "To Jack Reid . . ." inscription written across the face. If I find it any time soon, I'll post it.
Cables were very popular when steel for barbells was hard to come by and Liederman was one of several who touted mail order training manuals and cable sets.
Oh! I think he also used some general dips and chins and gymnastic movements in his routines. Note, that Liederman had fairly well-developed pectorals for someone in the pre-bench press era. Dips maybe? I can't recall. I always thought it made his posture look poor, sort of slump-shouldered and pulled forward a bit.
And, I don't ever recall any cross-over events, say, that he competed in weightlifting meets.