Ideally you would want at least two; a generic manual, Lyman 50th, and a manual from the manufacturer of the jacketed bullets you are using. Hornady, Speer, Nosler, etc. I have the newest Lyman 50th and a Hornady and Nosler manuals (plus a dozen older and odd manuals)...
There is way more in a reloading manual than just load data, which is why I use "full" reloading manuals and not compilations (one caliber load pamphlets). Even after 40 years of reloading it's nice to have charts, new info at hand.