ESPript is a PostScript-based program for the visualization of multiple sequence alignments. It allows the rapid visualization of sequences aligned with programs such as CLUSTAL-W or GCG PILEUP. ESPript can read secondary structure files, such as those created by DSSP, to produce a synthesis of both sequence and structural information. The program can be run via a command file or a friendly HTML-based user interface. It calculates an homology score by columns of residues and can sort this calculation by groups of sequences. It offers a palette of markers to highlight important regions in the alignment. ESPript can also paste information on residue conservation into coordinate files, for subsequent visualization with a graphics program. ESPript is available on its website at http://www.ipbs.fr/ESPript. Sources and help files can be downloaded via anonymous FTP from ftp.ipbs.fr. A tar file is held in the directory pub/ESPript. The program can read up to 98 sequences aligned on 2000 columns, retaining the alignment of the input file. Sequences can be displayed on up to 10 pages of PostScript. Parameters are fed in through the standard input, which is divided into seven steps. ESPript is written in FORTRAN77 and is developed on Silicon Graphics and DEC workstations at the IPBS, Toulouse. The present version, ESPript1.4, can be compiled using f77 or g77 and has been tested on most platforms (Unix, VMS, PC-Windows or Linux). A CGI script written in perl v 5.004 and relying upon CGI.pm v 2.39 or later is provided with the program. This script can be installed on a Web server, as has been done in Toulouse. The users can execute ESPript by filling the fields of an HTML form. Results are presented as hypertext links to PostScript files (or PDB files, if requested). These files can be viewed before retrieving, if the browser is properly configured. PostScript files can be converted into other graphics formats (jpeg, tiff, png), using a program such as GHOSTSCRIPT. ESPript offers a few tricks not routinely available in other programs, which can be used to build up information on the output file. It is possible to obtain an output from different files of aligned sequences or to select sequences for similarity calculations, which are not displayed on the PostScript. Information from two or more secondary structure files can be entered and related to a sequence chosen by the user. In addition, a PDB file can be produced with temperature factors replaced by similarity scores calculated with ESPript. This file can be passed to a graphics program to represent conserved areas by a colour code. ESPript is easy to use. In the simplest case, the user merely runs the program on-line, specifies the name of the alignmentESPript is a PostScript-based program for the visualization of multiple sequence alignments. It allows the rapid visualization of sequences aligned with programs such as CLUSTAL-W or GCG PILEUP. ESPript can read secondary structure files, such as those created by DSSP, to produce a synthesis of both sequence and structural information. The program can be run via a command file or a friendly HTML-based user interface. It calculates an homology score by columns of residues and can sort this calculation by groups of sequences. It offers a palette of markers to highlight important regions in the alignment. ESPript can also paste information on residue conservation into coordinate files, for subsequent visualization with a graphics program. ESPript is available on its website at http://www.ipbs.fr/ESPript. Sources and help files can be downloaded via anonymous FTP from ftp.ipbs.fr. A tar file is held in the directory pub/ESPript. The program can read up to 98 sequences aligned on 2000 columns, retaining the alignment of the input file. Sequences can be displayed on up to 10 pages of PostScript. Parameters are fed in through the standard input, which is divided into seven steps. ESPript is written in FORTRAN77 and is developed on Silicon Graphics and DEC workstations at the IPBS, Toulouse. The present version, ESPript1.4, can be compiled using f77 or g77 and has been tested on most platforms (Unix, VMS, PC-Windows or Linux). A CGI script written in perl v 5.004 and relying upon CGI.pm v 2.39 or later is provided with the program. This script can be installed on a Web server, as has been done in Toulouse. The users can execute ESPript by filling the fields of an HTML form. Results are presented as hypertext links to PostScript files (or PDB files, if requested). These files can be viewed before retrieving, if the browser is properly configured. PostScript files can be converted into other graphics formats (jpeg, tiff, png), using a program such as GHOSTSCRIPT. ESPript offers a few tricks not routinely available in other programs, which can be used to build up information on the output file. It is possible to obtain an output from different files of aligned sequences or to select sequences for similarity calculations, which are not displayed on the PostScript. Information from two or more secondary structure files can be entered and related to a sequence chosen by the user. In addition, a PDB file can be produced with temperature factors replaced by similarity scores calculated with ESPript. This file can be passed to a graphics program to represent conserved areas by a colour code. ESPript is easy to use. In the simplest case, the user merely runs the program on-line, specifies the name of the alignment