This book deals with, but is not limited to, the following: (1) A collection of typical computer programs written in Python and Matlab for scientific computations and their comparisons; (2) Interfaces of Php, Python, Perl with Matlab and vice versa; (3) Use of MySQL tables and XML for storing and transmitting scientific and economic data in scientific programming with Matlab, Python and Perl; (4) Converting from XML to MySQL tables and vice versa using Php; (5) Creating XML and MySQL tables and retrieving data from them for inputting to Matlab and to Python, using Php. It is assumed that the reader has had some knowledge of Php, Matlab, Python, Perl, MySQL and XML. As this book is written with Matlab programmers in mind, the following books are highly recommended for understanding the details of computer programs in this book: (1) Julie C. Meloni, PHP, MySQL and Apache,All in One, 4th ed. (2) Hans Petter Langstangen, A Primer on Scientific Programming with Python. (3) Robin Nixon, PHP, MySQL & JavaScript. K.Y. CHEUNG