John L. Kelley received his Ph.D. from The University of Virgnia in 1940. He taught at Notre Dame University and the University of Chicago prior to coming to the University of California at Berkeley. Since coming to Berkeley he has held visiting appointments at Tulane University, the University of Kansas, Cambridge University (as Fullbright Research Professor), and the Indian Institute of Technology at Kanpur. Professor Kelley is the author of several books and research articles on topology and functional analysis.
Many said this is a classic textbook in general topology. I agree with that as there are others on the same topic refer to this very often. Many theoretical topics appear as problems at the end of each chapter.
However, this should be used as a reference book instead of one to learn from. If you want a book to learn topology from, then I suggest General Topology by Stephen Willard and Topology by James Dungundji. Personally, I prefer Dugundji's for being encyclopedic and well-organized.