The coloring book activities throughout the course are quite important, despite the term 'coloring book'. There are several anatomy coloring books available including a free one.

Kaplan Anatomy Coloring Book
This one is free online. Do be aware that the pdf does pull the images from an online archiving organization, so if you are paying per mb for internet access, you may want to print of the pdf or get screenshots of each page at a large enough resolution to be able to read the text. It is OK as far as quality and coverage goes. There are better options that do cost money.

Kapit's Anatomy Coloring Book
I see this one reviewed as the best far more often that any of the other authors. Most mention the advantages ...
  • print on only one side of the page so you don't have to worry about bleed through
  • superscripts to group related parts
  • letters inside the structures rather than lines pointing to them
  • just the right amount of text
If you buy the coloring book used, be sure it is described as being free of coloring. This is supposed to be an activity book. Also, do not get the Kindle version for the same reason.
Note: Kapit also has a very highly regarded coloring book for physiology. Be sure to get the anatomy one and if you are going into a medical field the Kapit Physiology Coloring Bookwould be a good extra resource.

Barron's Anatomy Coloring Book
This one is often liked because it has a spiral binding. That makes it easier to lay it flat.

Muscolino's Anatomy Coloring Book
This one is often liked because it has many, many views of each structure. Like many of the other coloring books, the lines for labeling sometimes makes it confusing though.

Grey's Anatomy Coloring Book
This one has detail, lots of detail. Some students have said this one is harder to use than the others.