Top positive review
A brief, gentle introduction to a difficult subject
on 16 June 2017
This slim tome was my first formal encounter with topology, and I found it reasonably easy to work through on my own. Like many undergrad textbooks, it states that there are no prerequisites other than comfort with proof based maths. However, I would recommend making yourself familiar with basic analytic concepts and being comfortable proving theorems using them before starting the book. While none of this knowledge is strictly necessary for the book, an "analytic way of thinking" will be a helpful springboard into the material, as most of the new concepts covered in the book are presented as generalisations of concepts in Euclidean n-space.
It starts off covering the basics of set theory and functions, most of which can be safely skipped by anyone with a semester or two of undergrad under their belt, and merely used as a reference (though it would be a good idea to look at the bit about commutative diagrams for those studying at that level). Chapter 2 covers metric spaces, giving definitions of open sets, neighbourhoods and continuous functions between metric spaces (among other things) in terms of open balls, then linking these concepts through various theorems. Chapter 3 defines topological spaces, then defines various concepts on topological spaces using the by now familiar analogous concepts in metric spaces. Readers may notice that many of the definitions given in Chapter 3 are almost word-for-word copied from theorems in Chapter 2, by design. Chapter 4 introduces the various forms of connectedness, and investigates homotopic paths & the fundamental group, though it doesn't seem to give a formal definition of the FG anywhere. Chapter 5 introduces compactness of both topological spaces and metric spaces, relating this back to material in chapters 2 and 3.
While the exposition is mainly clear and concise, the book is somewhat light on examples in places and occasionally skips over some steps in examples which are not necessarily obvious to a first-time student of topology. The exercises are interesting, useful and have a good difficulty curve between the start and end of a section. The ink is a bit light in some places, which may make it difficult to read, but this can be forgiven due to the inexpensiveness of Dover books in general. While it lacks the depth and scope of weightier tomes such as Munkres, it lives up to its title, and makes a good, cheap first pass at a famously difficult subject.