The free physics text available on http://www.motionmountain.net
(so far, the 21 MB pdf file only)
has been reworked. Many improvements have been introduced throughout this
15th version of the text, which remains surprising and thought-provoking on
every one of its over 1000 pages. There are many new figures, an
explanation of the indeterminacy relation of thermodynamics, a new puzzle
on the way to catch bananas, the fundaments of dislocations, the reason
that mornings are quiet and evenings are not, the method used by whales to
communicate below water, and the story on how to swim through empty, but
curved space-time. The explanation of the microscope and the telescope,
the addition of accelerations in special relativity, and the fundaments of
topology and Lie groups have been included. There are now over 1300
problems, 600 solutions, 300 figures and 80 tables.

The section on quantum theory has been expanded; it now gives an improved
introduction to quantum theory. There is also a new section
called "Physics in limit statements" that summarizes special relativity,
electrodynamics, thermodynamics, general relativity and quantum theory in
five simple inequalities. Not only do they summarize most of 20th century
physics; they also allow to draw in simple ways some conclusions that are
important conceptual steps on the way towards the unified description of
nature. In this way, the section provides some background to Brian
Greene's discussion of space-time in "The elegant universe".

The maximum force principle is explained in more detail than
before. It is shown how to deduce the field equations of general relativity
from the simple statement that no force in nature is larger than c^4/4G.
In this way general relativity gets accessible in its main lines
to everybody with a secondary school degree.

In general, for all fields of physics the newest research results and the
main open questions are presented. The text remains a structured walk
through classical physics, relativity, quantum theory and unification. It
should appeal to everybody with an interest for physics. The reader gets a
vivid and entertaining overview of how motion can be described and of what
it can effect.

Enjoy!

Christoph Schiller

P.S. Thank you to all readers who have provided suggestions and
corrections. They are all mentioned in the foreword (I hope
I did not forget anybody).

Proposals for colour images to be added to the future text versions (with
permission) are much appreciated.

***