Preface. Introduction to the Fourth International MEOR Conference (F. Burtch). Plenary Address: "M.O.R.E." to M.E.O.R.: An Overview of Microbially Enhanced Oil Recovery (T.R. Jack). Selection and Characterization of Microbial Systems. Use of Natural Microflora, Electron Acceptors and Energy Sources for Enhanced Oil Recovery (G.T. Sperl, P.L. Sperl, D.O. Hitzman). Bug Rock: Bacteriogenic Material Precipitation Systems for Oil Patch Use (T.R. Jack et al.). Chemical Markers of Induced Microbial Transformations in Crude Oils (E.T. Premuzic et al.). Characterization of Xanthan Gum Degrading Enzymes from a Heat-stable, Salt-tolerant Bacterial Consortium (J.A. Ahlgren). Subsurface Application of Alcaligenes eutrophus for Plugging of Porous Media (Y. Li et al.). Halotolerant and Extremely Halophilic Oil-oxidizing Bacteria in Oil Fields (S.S. Belyaev et al.). The Use of Slime-forming Bacteria to enhance the Strength of the Soil Matrix (I.C.Y. Yang et al.). Parameters Affecting Microbial Oil Mobilization in Porous Media (A.K. Stepp et al.). Behavior of Microbial Culture Product (PARA-BACR) Isolates in Anaerobic Environments (D.R. Schneider). Aqueous Microbial Biosurfactant Solutions Exhibiting Ultra-low Tension at Oil-water Interfaces (T. Ban, T. Sato). The compatibility of Biosurfactants on Degassed Oil and the Displacement Efficiency of Biosurfactant/Sulphonate - Alkaline - Polymer System (S.-T. Gao, T.-L. Qin). Comparative Analysis of Microbially Mediated Oil Recovery by Surfactants Produced by Bacillus licheniformis and Bacillus subtilis (S.L. Fox et al.). Noninvasive Methodology to Study the Kinetics of Microbial Growth and Metabolism in Subsurface Porous Materials (M.J. McInerney et al.). Adhesion of Microbial Cells to Porous Hydrophilic and Hydrophobic Solid Substrata (T. Ban, S. Yamamoto). Modeling of MEOR. A Mathematical Model for Microbially Enhanced Oil Recovery Process (X. Zhang, R.M. Knapp, M.J. McInerney). Effect of Hydrophobicity of the Solid Substratum on Oil Displacement in the Hele-shaw Model (T. Ban, H. Kamo). Field Applications. Microbially Enhanced Oil Recovery Field Pilot, Payne County, Oklahoma (J.D. Coates et al.). Microbial Hydraulic Acid Fracturing (V. Moses et al.). A Pilot Test of EOR by In-Situ Microorganism Fermentation in the Daqing Oilfield (C.Y. Zhang, J.C. Zhang). The Application of Microbial Enhanced Oil Recovery to Trinidadian Oil Wells (U. Maharaj, M. May, M.P. Imbert). MEOR, Recent Field Trials in Romania: Reservoir Selection, Type of Inoculum, Protocol for Well Treatment and Line Monitoring (I. Lazar et al.). Microbial-Enhanced Waterflooding Field Pilots (R.S. Bryant et al.). Microbial Characteristics and Metabolic Activity of Bacteria from Venezuelan Oil Wells (H. Bastardo, L. Vierma, A. Estevez). A Nutrient Control Process for Microbially Enhanced Oil Recovery Applications (G.E. Jenneman, J.B. Clark, P.D. Moffitt). Characteristics of Enriched Cultures and their Application to MEOR Field Tests (X.-Y. Wang, Y.-F. Xue, S.-H. Xie). On-site Bioaugmentation Treatment of Petroleum Tank Bottom Wastes: A Case Study (F.K. Hiebert et al.). Six years of Paraffin Control and Enhanced Oil Recovery with the Microbial Product, Para-BacTM (L. Nelson, D.R. Schneider). Causes and Control of Microbially Induced Souring (M.J. McInerney et al.). Additional Oil Production During Field Trials in Russia (M.V. Ivanov et al.). Isolation of Thermophilic Bacteria from a Venezuelan Oil Field (G. Sanchez, A. Marin, L. Vierma). Potential of MEOR. The Potential for MEOR from Carbonate Reservoirs: Literature Review and Recent Research (R.S. Tanner et al.). Using Bacteria to Improve Oil Recovery from Arabian Fields (M.H. Sayyouh, M.S. Al-Blehed). On Towards the Real World (V. Moses). Abstracts. Comparison of the Properties of Commercial Xantham Gum with a Xantham Gum Produced by Xanthomonas campestritm Using Lactose as Sole Source of Carbon (F. Paz, G. Trebbau, L. Vierma). A Mathematical Model to Optimize Fermentation in Xanthomonas campestris (E. Rodriquez). Thermophilic Bacteria from Petroleum Reservoirs (G. Grassia, A.J. Sheehy). Index.