Infinite Series (Dover Books on Mathematics)

It is generally ok for math lover at collage level. But the material is not detailed enough, not that comprehensive.

To read it and understand some of it, you will need already an introduction to sequences and series. I used a pre-calculus book to review sequences and basic series. From there, you are able to read the first chapters. It is an advanced math. book.

I was looking for extended material on various elaborations and permutations of geometric series and exponential growth, and declining exponential growth for my own uses, and did not find it, so I was disappointed. However, the material is quite extensive otherwise; purely for math instructors, students, enthusiasts.