Incredibly, most of the information in this book is still current. I have several books on beekeeping, and while every author has his own hints and tips, most of the basics were laid down by Langstroth, and the enthusiasm that he has for his bees is infectious and inspiring.
A couple of minor caveats: the information here is extremely dense and the older writing style can be a little hard going. There is - as would be expected - much less cross-referencing and indexing than you might find in a modern book where such things can be automated. As others reviewers have mentioned, Langstroth comes across as a bit of a know-it-all, although that's probably because he DID know it all. None of this detracts from the immense value of this book, which is a bargain at 0.00.