This software is designed for photographers to make adjustments to a digital image. While Photoshop has been traditionally used to make those adjustments, I have always thought that Photoshop is an overkill. I confess I did not immediately take to Lightroom. In fact I went as far as deleting it a couple of days after downloading and installing the trial version. Even now I still immensely dislike the "Library" function, which is actually a cataloging function that can potentially lock you into a rigid system of managing your files and folders. Thanks, but no thanks, Adobe.
The "Develop" module is what I love about Lightroom. It truly simplifies all the tasks a photographer would typically need to do on a digital image. There are no "layers"; which I say is the life and soul of Photoshop, and the bane of one trying to learn Photoshop for the first time. Instead, all changes are done virtually on one page and can always be completely reverted back to the original. The best part of all is that it can be learned fairly quickly, so that the photographer can stick to shooting pictures without having to master Photoshop as well. Having said that, it is only fair to say that Photoshop is still the king of digital manipulation, so don't expect Lightroom to do everything.