This is an archive of the old MediaWiki-based ImageJ wiki. The current website can be found at imagej.net.
User Guides
The ImageJ User Guide provides a thorough description of ImageJ's built-in functions.
The Fiji Cookbook provides an analysis-oriented introduction and user guide to ImageJ.
Analyzing fluorescence microscopy images with ImageJ provides detailed information on image analysis using ImageJ.
A textbook for constructing bioimage analysis workflows using ImageJ macro, Matlab and R, to extract numbers out of image data. Freely downloadable from Wiley site.
Fiji Training Notes including demo images from Monash University. Detailed screenshot and explaination steps on basic analysis through to macro code