The articles in this part of this issue of the journal are a selection of the papers originally presented to the Fifth Workshop on Coalgebraic Methods in Computer Science. CMCS was held in April 2002, in Grenoble, France as a satellite conference of ETAPS. The conference proceedings were published in Electronic Notes in Theoretical Computer Science65 (1). There were fifteen contributed papers and two invited talks. Six papers were selected by the Program Committee after a meeting for consideration of this issue, and revised versions were then sent to referees. In consultation with them, I selected the four published here. Most of them were later revised, so, in general, the papers appearing here are improved versions of the conference versions.