This book is the final product of a conference organized at the Free Univer sity, Amsterdam, by some members of the Dutch Human Performance Group and sponsored by the Dutch Psychonomic Society. We first of all thank the Society for financially supporting this publication, and the Free University for providing technical support. P.J.G. Keuss, A.A.J. Mannaerts, and W. Hulstijn, members of the organizing commitee, and J.A. Michon and W. Molenaar collaborated with the editors in defining the fields dealt with at the conference and in the book and in getting together the team of authors. All the...