When I reload I have two methods.
If I'm lacking in time or loading for just fun shooting at the range i'll grab either "Modern Reloading" by richard Lee or the Lyman 48. I very much lean to the Lyman if I'm going to use lead bullets.
If I'm trying to work up an accurate load for a particular bullet then I'll use the manual from that bullet's maker, IE Sierra manual to Sierra bullet, Hornady to Hornady, Nosler to Nosler, Speer to Speer etc. etc.
If I were limited to one then the Lyman. Lead bullet references along with jacketed references. As long as I kept the most recent edition copy on hand.