The book "General Topology" by Ryszard Engelking is widely available in print and electronic formats. You can find it on online bookstores such as Amazon, Google Books, and the American Mathematical Society (AMS) website.
Some authors allow chapter-by-chapter PDFs for personal use. Engelking did not, to my knowledge, release the book openly. Therefore, downloading a full PDF from LibGen or similar sites is piracy . engelking general topology pdf
Engelking suggests a specific "introductory" path for those new to the text before branching into specialized topics: The book "General Topology" by Ryszard Engelking is
: Fundamental definitions of topological spaces, continuous mappings, bases, subbases, and closure/interior operators. Chapter 2: Operations to my knowledge