In this small but very significant book, you will find 101 problems of indefinite integrals solved step by step, explained by means of formulas and mathematical properties applicable to each type of exercise.The types of indefinite integrals described in this work are those corresponding to the topics of unit two of the Integral Calculus course of the engineering programs of the Technological Institutes belonging to the Tecnológico Nacional de México (TecNM). In addition, you will find simple integrals that will increase the degree of difficulty until reaching the integration methods.