**Packages Maple and Mathematica are indisputable leaders among modern systems of computer algebra systems. In this connection there is quite natural question about preferability of either of these systems. This question is rather multidimensional in view of multifunctionality of both packages. In this connection in the book the comparative analysis of both packages concerning opportunities of their software environments for modular programming of the user problems of various orientation is submitted. The content of the book is submitted by 10 chapters, namely: **

**1. Brief excursus into the history of computer algebra systems **

2. The general information on programming languages Maple and Mathematica

3. Base control structures of packages Maple and Mathematica

4. Mechanisms of typification of objects in the environment of both packages

5. The organization of processing of special and erroneous situations

6. The organization of mechanism of procedures and modules in Maple and Mathematica

7. The organization of work with packages in the Mathematica environment

8. Means of input/output of packages Maple and Mathematica

9. The organization of the user software

10. Maple or Mathematica - a subjective standpoint