Why study Neoclassical Economics?
Neoclassical economics looks at the world through a deceptively simple prism: that of scarcity, prices and markets. It shows how prices contain information about what goods are desired and what goods are scarce. Thus, through the price level entrepreneurs are informed what they should produce. It is often attacked for its strong and unrealistic assumptions, like fully rational human people with no social ties, the assumed existence of markets without (violent) conflict or power struggles, and the omission of social or ecological factors from its basic framework. But it provides a simple and powerful analysis worth diving into!
Where to start?
Buy any textbook about economics and the chance is 90% that you'll be holding a largely neoclassical work. For a critical view on the approach, start with Dani Rodrik's Economics Rules, or The Death of Neoclassical Economics by David Colander. Exploring Economics provides a more extensive definition of the approach, including many useful sources, and What is Neoclassical Economics goes even deeper into defining the approach.