Q:1 So far, after studying chemistry for two years I am unable to figure out any well-defined methodology of handling a particular reaction either in General or Organic chemistry. So I would appreciate If some one could point out some useful source(book etc) where I could look deeply into the back ground of the chemical reactions.
Q:2 If we are given for example two or three reactants is it possible to determine how they will react?
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Welcome to ChemSE. Your first question is rather broad; both because of the large body of books (and sources, in general) about Chemistry, and because it is not further specified what you already learned by self study. Similar questions already were addressed on ChemSE, like here, or here; and more generally surveyed in a synopsis here. However, none of them aims to be exhaustive, none of them considers what kind of self-study fits you best.
Regarding the second question by you, reactions with more than two starting material are not rare. In the Friedel-Crafts acylation, for example, you have both an arene and an acylchloride reacting with each other to yield a ketone, however, often you need a Lewis acid (like $\ce{AlCl3}$) promoting the reaction:
(source)
which however rarely is seen as a complex reaction in terms of the number of reagents involved. There are, however, reactions summarized as multi-component reaction, where, like in the Ugi reaction, several reagents are present at the same time in the same reaction vessel to yield the product.
(source For clarity, the starting materials are colour encoded.)
Even here one was able to postulate a reaction mechanism:
(source).
