What books should I choose for my modern book collection?

My collection of books, I favor textbooks, an introductory textbook of a subject. One is because if you want to study a subject in depth, you must have the time and energy and the use of a place to do so, the second is to two or three streams of undergraduate qualifications, they can read the book on the understanding of the book on the line, as for the language and the title of a very long book will not need to spend more money. After reading it should not always be proud to say that they are professional, at best, to say that the introduction. You should know that the degree of professionalism of the books published and distributed on the market has been many years behind than in the Institute, far from the academic journals. Therefore, books should be read with a humble attitude. Any discipline that represents not the whole of the facts, but a perspective on the problem, only to bring us closer to the truth.