In this paper families of almost-disjoint, countably infinite sets will be considered, i.e. families of type ~r e~z) where [A.[=~o and tA~NAp] is finite whenever 0~3<• One of the early results in the theory of almost-disjoint sets is the following theorem of E. W. Miller [3]: if d = (A~: e < x) is a family of infinite sets and instead of almost-disjointness the stronger ]A, NA~]<-n holds with a fixed n