Description from Google Books:

The creator of the popular webcomic "xkcd" uses line drawings and just ten hundred common words to provide simple explanations for how things work, including microwaves, bridges, tectonic plates, the solar system, the periodic table, helicopters, and other essential concepts.

Snippet from Google Books:

The creator of the popular webcomic "xkcd" uses line drawings and just ten hundred common words to provide simple explanations for how things work, including microwaves, bridges, tectonic plates, the solar system, the periodic table, ...

Description from Harvard Library:

The creator of the webcomic "xkcd" uses line drawings and just ten hundred common words to provide simple explanations for how things work, including microwaves, bridges, tectonic plates, the solar system, the periodic table, helicopters, and other essential concepts.