What is the best book for metric space

There is a wonderful short book by Kaplansky called Set Theory and Metric Spaces. but some standard books which are very good rudin, s.kumaresan

for metric space best books are Satish sirali and s.kumaresan , these books have every conceptual problems that you can understand easily..

Topology of metric spaces by S kumaresan ....I will suggest you this book .....It has lots of problem with nice theoretical approach