The composer writes: ëAlthough I had not originally conceived Spook as having any sort of extra-musical associations, when it came time to find a title for the work I thought of the mercurial nature of much of the music. Like a ghost, glimpsed in the corner of your eye and vanishing when you spin round to look at it, the substance of the music is elusive, the tonality continually shifting and the patterns of repeated figures subtly changing as soon as they can be grasped.í In some respects Spook is a technical etude for the marimba. The main body of the work focuses almost exclusively on the use of the double lateral stroke, one of the virtuoso innovations of the last few decades. With four mallets available, extremely high velocities can be achieved by playing two consecutive notes with each hand instead of with the traditional left hand, right hand figuration. The quieter contrasting moments emphasise the independent roll, where instead of executing a roll between the two hands, the roll is played between the two mallets of a single hand. Sustained chords are played by one hand as an accompaniment to the other, which plays more articulate, rhythmic material. After a steady build-up to a powerful climax which utilises the full range of the marimba keyboard, the music subsides before setting off on an even faster coda, a percussive frenzy of slowly rising patterns and accents which culminates in a clatter of open fifths in the very lowest register of the instrument.