A. Abiotic Aspects.- I. Origins.- I.1. Formation and geological evolution.- References of chapter I.- II. Geomorphology and Sedimentation.- II.1. Morphology and bathymetry.- II.2. General aspects of present-day sedimentation.- II.3. Temporal sedimentation patterns in the nearshore littoral of Lago Huiñaimarca.- References of chapter II.- III. Paleohydrology.- III. 1. A 20,000 years paleohydrological record from Lake Titicaca.- III.2. Ancient lake environments as deduced from pollen analysis.- References of chapter III.- IV. Climatology and Hydrology.- IV. 1. Climatology and hydrology of the Lake Titicaca basin.- References of chapter III.- V. Physico-Chemistry.- V.1. Physico-chemical properties of the water.- V.2. Hydrochemical regulation of the lake and water chemistry of its inflow rivers.- V.3. Dissolved matter and suspended sediment loads in some inflow rivers and in the Rio Desaguadero.- V.4. The thermal stratification regime in Lake Titicaca.- V.5. The energy balance.- V.6. Nutrients and nutrient limitation of phytoplankton.- References of chapter V.- B. Biological Communities.- VI.1. Phytoplankton.- VI.1a. The diatoms.- VI.1b. Algae: General floristic study.- VI.1c. Phytoplankton: Quantitative aspects and populations.- VI.1d. Patterns of planktonic primary production and algal biomass.- References of chapter VI.1.- VI.2. Macrophytes.- VI.2a. The higher plants.- VI.2b. Charophytes.- VI.2c. Higher plants: Distribution and biomass.- References of chapter VI.2.- VI.3. Zooplankton.- VI.3a. The Cladocera.- VI.3b. Zooplankton distribution in the Bolivian part of the lake.- VI.3c. Temporal and spatial variation of Zooplankton in Lago.- VI.3d. Note on the feeding behaviour of Zooplankton.- References of chapter VI.3.- VI.4. Benthic Fauna.- VI.4a. The Bryozoa and Coelenterata.- VI.4b. The Porifera: Description of a new taxon Balliviaspongiawirrmanni n.g. n.sp..- VI.4c. The benthic oligochaetes.- VI.4d.The Tricladida and Hirudinea.- VI.4e. The Mollusca.- VI.4f. The Ostracoda.- VI.4g. The Amphipoda.- VI.4h. The Hydracarina.- VI.4i. The insects.- VI.4j. The benthic populations: Distribution and seasonal variations.- References of chapter VI.4.- VI.5. Fish Fauna.- VI.5a. Native species. The Orestias.- VI.5b1. Introduced species: 1. Salmo gairdneri (rainbow trout).- VI.5b2. Introduced species: 2. Basilichthys bonariensis (the “Pejerrey”).- References of chapter VI.5.- VI.6. Associated Animal Communities.- VI.6a. The Amphibia.- VI.6b. The Ophidians.- VI.6c. The avifauna.- References of chapter VI.6.- C. Exploitation of the Lake Resources Socio-Economic Aspects and Contamination.- VII.1. Ethnology and Socio-Economy.- VII.1a. Past and present human populations.- VII.1b. Former lake fisheries and fish fauna of the lake.- VII.1c. Social and economic aspects of the fisheries.- VII.1d. The socio-economic importance of macrophytes.- VII.1e. Influence of the lake on littoral agriculture.- References of chapter VII.1.- VII.2. Hydrological Potential.- VII.2.a. The water resources.- References of chapter VII.2.- VII.3. Ichtyological Potential.- VII.3a. The fishery potential.- References of chapter VII.3.- VII.4. Contamination.- VII.4a. Eutrophication and pollution problems.- References of chapter VII.4.- Geographical and Subject Index.- Taxonomic Index.