To guarantee the reliability of critical editions, electronic tools are indispensable, not only for publishing (in conventional or electronic form), but above all for the preparation of text, apparatuses, indexes. The tools to be presented start from automatic collation of different versions of the same text as presented in the witnesses (manuscripts, typescripts, early printings); they allow for the integration of the results of conventional collation (after transcribing them electronically). The demonstration includes a synoptic printout of the text and the different versions as contained in the witnesses as a first overview over the tradition of a text. It also includes tools for semi-automatically separating the "minor" variants (like pure orthograpical variation or differences in punctuation) from "substantial" ones to be included in the critical apparatuses, and the sorting and formatting procedures required for automatic generation of apparatus entries (including reference to the copy text, lemma, variants, manuscript codes, markup). Though (except for very simple cases) fully automatical generation of critical apparatuses is neither desired nor possible, these tools can take over much of the burden of carefully and safely administrating the materials gained from the witnesses and thus allow the user to concentrate on the editorial problems. The editor has in every stage perfect control over the results of the automatic steps during the preparation of the text and the different aparatuses. This includes the possibility both to refine the rules for the automatic process and to revise the results manually where the rules can not be adapted (e.g. to ambiguous cases) without unreasonable effort. The demonstration includes the tools to incorporate the apparatus entries into the text and adding the markup as required for conventional or electronic publication. Automatic page makeup (for paper edition) and automatic conversion into a full text retrieval system will conclude the demonstration. The procedures which will be demonstrated have been programmed using the TUebingen System for TExt Processing TUSTEP, which is a flexible and very powerful programming environment for handling textual data. It runs under MS-DOS, VMS (DEC VAX machines), and different UNIX dialects (presently: Interactive UNIX, LINUX, AIX, ConvexOS, Digital UNIX (OSF/1), HP-UX, IRIX, SunOS/Solaris). The DOS version does not include the typesetting routines. In addition to the preparation of critical editions (the list of editions prepared and published with TUSTEP contains over 150 titles), TUSTEP is beeing successfully used for lexicograpy, bibliographic work (well known examples are the periodicals "Germanistik" and "Romanische Bibliographie"), concordances, and literary and linguistic analysis.