Knuth says:

For many years I've resisted temptations to put out a hasty electronic version of The Art of Computer Programming, because the samples sent to me were not well made.

But now, working together with experts at Mathematical Sciences Publishers, my publishers and I are launching an electronic edition that meets the highest standards. We've put special emphasis into making the search feature work well. Thousands of useful "clickable" cross-references are also provided --- from exercises to their answers and back, from the index to the text, from the text to important tables and figures, etc.

The first fascicle can now be ordered from Pearson's InformIT website, and we expect to release thousands of additional pages next year.

http://www-cs-faculty.stanford.edu/~knuth/news.html