The primary objective of this paper is to describe 18 species and five subspecies mainly based on recent collecting under the auspices of the African Butterfly Research Institute, Nairobi (ABRI).  The 23 new taxa are: Graphium almansor dufranei Collins & Larsen, spp. nov.; Cooksonia abri Collins & Larsen, sp. nov.; Cooksonia ginettae Collins & Larsen, sp. now.; Liptena lloydi Collins & Larsen, sp. nov.; Liptena minziro Collins & Larsen, sp. nov.; Liptena liberti Collins, Larsen & Libert, sp. nov.; Liptena bia Larsen & Warren-Gash, sp. nov.; Iridana agneshorvathae Collins, Larsen & Sáfián, sp. nov.; Hewitsonia kuehnei Collins & Larsen, sp. nov.; Aphnaeus marci Collins & Larsen sp. nov.; Iolaus (Philiolaus) ofere Collins & Larsen, sp. nov.; Iolaus (Epamera) adorabilis Collins & Larsen, sp. nov.; Bicyclus sealeae Collins & Larsen, sp. nov.; Bicyclus pareenss sp. nov.; Collins & Kielland; Bebearia staudingeri okomu Collins & Larsen, ssp. nov.; B. staudingeri carensis Collins & Larsen, ssp. nov.; Pyrrhochalcia iphis dejongi Collins & Larsen, ssp. nov.; Abantis ja usheri Collins & Larsen, ssp. nov.; Gorgyra warreni Collins & Larsen, sp. nov.; Meza gardineri Collins & Larsen, sp. nov.; Acleros bobiri Collins & Larsen, sp. nov.; Platylesches heathi Collins & Larsen, sp. nov.; P. hassani Collins & Larsen, sp. nov.  A dozen nearly unknown and/or misunderstood species are also discussed, and a number of these have their types figured in colour for the first time: Colias marnoana, Eresina cornucopiar, Falcuna melandeta, Iolaus likpe, Thermoniphas bibundana, T. leucocyanea, Bebearia denticula, Pseudathyma legeri, Acraea Eugenia echreata, Platylesches langa, and P. batangae.  Pteroteinon reali Berger, 1962, hitherto treated as a subspecies of P. pruna Evans, 1937, is elevated to specific rank (stat. nov.) and is a senior subjective synonym of Caenides na  Lindsey & Miller, 1965 (syn. Nov.). The species Euriphene larseni is formally downgraded to a junior subjective synonym of E. saphirina itanii.  We also hope that the paper will provide some impression of the research processes at ABRI.  The status of our present knowledge of African butterflies has improved considerably during the past 15 years, but much remains to be done.