Dear colleagues - After taking far too long, I have made a modified version of my thesis entitled "An algebraic theory of tricategories" available at www.math.yale.edu/~mg622/tricats.pdf. If you have questions, comments, find more typos, or anything of that sort, I encourage you to write to me at michaeln.gurski@yale.edu. Thanks to everyone who bugged me about making this available, and thanks for being patient. Nick Gurski