Adapted from Stephen Wolfram's definitive work A System for Doing Mathematics by Computer, 2nd Ed., this is the beginning student's ideal road map and guidebook to Mathematica. This adaptation addresses the student's need for more concise and accessible information. Beck has trimmed to book to half its original size, focusing on the functions and topics likely to be encountered by students.
Stephen Wolfram is the founder & CEO of Wolfram Research, creator of Mathematica, Wolfram|Alpha & Wolfram Language, author of A New Kind of Science and other books, and the originator of Wolfram Physics Project.
Mathematica: The Student Book, Stephen Wolfram, 1994, for Mathematica version 2, 501 pp. Library-of-Congress QA76.95.B43 1994 Steenbock Library. ISBN 0201554798.
All this content is probably in Stephen Wolfram's 2005 The Mathematica Book, 5th edition, for Mathematica version 5.
However, the smaller, older book, may be easier to find what you need in.
Also, Wolfram here explicitly tells us of key features that aren't apparent elsewhere, such as:
"The standard notebook interface for /Mathematica/ allows you to specify certain cells of /Mathematica/ input as being "initialization cells". These cells can contain definitions and results that are automatically set up again whenever you open the notebook." Well, hallelujah! That will be very handy, not to have to re-evaluate every expression in the notebook every time I reopen the file. This 1994 book says it on p. 278, section 29.1. I hadn't seen this in any other documentation.