I do a fair amount of solo gaming, usually on my bi-weekly laundry night. Like Barnes, I sometimes solo games that aren't designed for solitaire play. So when I heard about The Solo System, I had to get it. It's about the size of a deck of cards, but actually has four sub-decks of cards, and supplies a very basic level of AI when you are solo-playing a non-solitaire game. One set of cards address strategy, one does tactics, another for movement, and one even addresses bidding and miscellaneous decisions. Out of the box, I think The Solo System offers a limited value. But if you really have a particular game that you want to solo, it might be better to make your own set of cards for that specific game, inspired by the cards in The Solo System.