My initial reaction after browsing through Kantoku's second art book, titled STEP Kantoku Art Works, was that I should really stop purchasing his doujinshi. This isn't a testament to it being a bad art book, on the contrary, it's excellent. But it does mean that much of the contents from this book (as well as the last one) were initially published in his doujins.
Ashiato ~Kantoku Art Works~ (あしあと~カントクアートワークス~) turns out to be as colorful and vibrant as expected, filled with 144-pages of beautiful girls ranging from original creations to copyright characters. The book is B5 sized, so it's smaller than most art books, but about the size of the average doujinshi.