The 12th meeting on Frankia and Actinorhizal Plants that took place in Carry-le-Rouet, France in June 2001 was the opportunity for scientists to communicate about latest developments on this symbiosis that concerns a wide range of dicotyledonous plants, initiates ecological successions and is used in a number of countries to protect crops from winds or improve soil status. Selected papers on plant ecology, Frankia's genetics or physiology, and host plants' genetics or physiology are published in this special Plant & Soil issue.Proceedings of the 12th meeting on Frankia and actinorhizal PlantsThe 12th meeting on Frankia and Actinorhizal Plants that took place in Carry-le-Rouet, France in June 2001 was the opportunity for scientists to communicate about latest developments on this symbiosis that concerns a wide range of dicotyledonous plants, initiates ecological successions and is used in a number of countries to protect crops from winds or improve soil status. Selected papers on plant ecology, Frankia's genetics or physiology, and host plants' genetics or physiology are published in this special Plant & Soil issue.1. Introduction.2. Frankia inoculation, soil biota, and host tissue amendment influence Casuarina nodulation capacity of a tropical soil; J.F. Zimpfer, et al.3. An assessment of soil enrichment by actinorhizal N2 fixation using delta15N values in a chronosequence of deglaciation at Glacier Bay, Alaska; S.J. Kohls, et al.4. Effects of land irrigation with partially-treated wastewater on Frankia survival and infectivity; W.F. Sayed.5. The production and utilisation of monoclonal antibodies for identification of a Frankia strain utilised as inoculum for Casuarina equisetifolia; A. Hahn, et al.6. The effects of fire on soil nitrogen associated with patches of the actinorhizal shrub Ceanothus cordulatus; B.B. Oakley,l"