You have to have enough aces. If the defense has two cashable aces, you'd better stay in game. Furthermore, the king of trumps is so important that you shouldn't be in slam if you miss an ace and the trump king.
   All side suits should be controlled. If one of your side suits is two small opposite queen third, you can't make a slam, since the defense can start by cashing two tricks in the suit.
   You should be able to play the trump suit for at most one loser.
   You need playing strength for slam. Even if the first three conditions are fulfilled, it's stupid to be in slam if you never can take twelve tricks.

If you are playing a grand slam, the same applies, except that you now can't lose a single trick in the trump suit or in any of the side suits.
  Since you have four different things to consider, it's obvious that one slam tool isn't enough. You need more. In this book the authors show in detail how you ask for aces, cue-bid, make a trump ask or finds out if the cards fit – like when you have three small cards opposite partner's void. When the fit is great, you may make a slam with much less strength than needed otherwise.
  The book is ended with some new ideas which may be of interest to people dedicated to bidding theory.

Published in 1988
ISBN 91-87416-01-8
The title is out of stock on Scania Bridgekonsult, but can be ordered from Svenska Bridgeförlaget.