Neither Isis Unveiled or The Secret Doctrine, nor both taken together unveil all the secrets of nature.
Nature contains all.
While she is sensitive to man's prying. She retains her secrets so long as man approaches with a selfish motive, which, being used, might eventually harm both himself and Nature. HPB spoke quite carefully in her introductions to those two books, advising us, her readers that they unveiled sections of what was invisible to most of us. If one then turns to page 305 in that book she continues giving information on the subject. It is not the Names of the claims that are important, but the knowledge that we can use and consider that is valuable.