i'm absolutely a newcomer in economics and i wish to understand how things work around finance.
This is a pretty loaded question. To understand finance, you need the basics of economics. In almost every economics school in the country, you first study microeconomics and then economics. So, we'll start with micro. One of, if not the, most popular books is "Principles of Microeconomics" by Mankiw. This book covers the fundamentals of micro econ (opportunity, supply, demand, consumer choice, production, costs, basic game theory, and allocation of resources) in a clear and effective manner. It's designed for the novice and very easy to read.
Like Mankiw's other book, "Principles of Macroeconomics" is also top notch. There is some overlap in key areas (i.e. opportunity cost, supply, demand, indifference curves, elasticity, taxation) because they are fundamental to economics and the overlap will always be there, but from there the book goes into key macro concepts like GDP, CPI, Employment, Monetary and Fiscal policy, and Inflation. An excellent intro primer indeed.
Now that you have the fundamentals down, it's time to learn about finance. The best resource, in my opinion, is "Financial Markets" by Robert Shiller on Open Yale Courses. I've personally taken Prof. Shiller's class last semester, and the man is brilliant. The lectures cover every single aspect of finance and can turn the complete novice into a fairly experienced finance student. The first lecture also covers all the math required so you don't get lost at any point. Be warned, however, that the course is very deep. We used Fabozzi's textbook "Foundations of Financial Markets and Institutions," which is over 600 pages deep and we were required to know essentially all of it. Watch the videos and follow the readings and you'll be a finance whiz soon!
Financial Markets on Open Yale
And that's your roadmap to what you want. There are other economics books and it's true that the first few chapters of both Mankiw books are largely the same, but that's because any economics course always covers the basics first. If you want to look at other books, Krugman has written some good books as well. Be sure to read reviews because some books are meant for 2nd/3rd year econ students, so you don't want to get a too advanced book. At the novice level, we're interested in understanding the basic concepts so we can master Fabozzi.
As for finance books - Fabozzi teaches you all the fundamentals of financial markets so you've got a powerful foundation. From there you can expand to more niche books such as books on investing or on monetary policy or whatever you want. Best of luck!