Given that over 40 years translates out into a lot of comics, and given that the official collectors edition dvds and Marvel Digital Unlimited mean that almost all of this backlog is easily available, it's sometimes hard to find the kind of issue you're looking for. Namely, one in which the characters you're interested in actually interact, or even one in which actual significant plot occurs.
To that end, I've tried to create a very simple, extremely informal guide to Captain America comics written before Marvel's Civil War.
In no way are most of these intended as reviews or judgement calls. They're just meant as a way of telling which characters make a major appearance in an issue, and what plot or fannish interest elements it might contain - with slight snark thrown in to keep me from getting bored.
NOTE: At this time, this project is incomplete. Captain America vol 1 remains unaddressed for the present. More forthcoming eventually.
The Complete Captain America vol 2
The Complete Captain America vol 3
The Complete Captain America vol 4
Captain America vol 5, issues 1-21, up to Civil War