Pedodiversity analysis is a rapidly growing area of scientific investigation. The concepts and tools were introduced to the field of the pedology in 1990 by Ibáñez et al. in the Catena Journal. After 1990, several soil scientists completed interesting studies with contributions that addressed theory, methodologies and applications (e.g. J.J. Ibáñez and J. D. Phillips among others). At the same time, essays at different spatial scales and using distinct protocols began to offer a scientifically sound framework of the potential for these techniques to analyse soil spatial pattern analysis, and soil geography, as well as testing pedogenetic theories (e.g. termed “divergent pedogenesis”). More recent studies have applied pedodiversity tools in order to successfully analyse the mathematical structure of pedological classifications. Thus, pedodiversity is not simply analysis of the pedotaxa number in a given area or region, where some regularities have been observed at different scales and in the most disparate situations and environments. In turn, new challenges begin to be tackled such as the case of the scale invariance of pedological structures, spatial pedotaxa and soilscapes distributions. Furthermore comparisons with diversity patterns detected in related disciplines (earth sciences, biodiversity, etc.) show surprising similarities with the pedological ones, opening new possibilities to detect regularities between different natural resources. Likewise, against the opinion of some geostatisticians, there are not scientific or epistemological arguments to use classical soil classification that separates the soil pattern continuum into discrete classes, as also occurs in ecology and related disciplines. It is possible that pedodiversity analysis could be applied to other pedological entities using either novel or well known mathematical techniques, such as geostatistical ones. The following table summarizes a scheme outlining the current state of the art in pedodiversity studies: 1. Introduction: Soils as part of our biological and geological heritages 2. Pedodiversity Analysis: Concepts and measurements 3. Comparing, pedodiversity, biodiversity, and geodiversity patterns a. General similarities and differences b. Soil types and habitat diversity c. Matching taxonomic pedodiversity, geodiversity and aboveground biodiversity d. Matching taxonomic pedodiversity and belowground biodiversity e. Pedodiversity as surrogate indicators of aboveground biodiversity and soil biodiversity 4. Preserving soils in the natural state 5. Preserving pedodiversity and its role in soil monitoring programs 6. Toward the design of national and translational networks of soil reserves 7. Improving our tools in soil geography studies 8. Studying the soil system from a complexity sciences perspective 9. Testing pedological theories (e.g. divergent pedogenesis) in the framework of non-linear systems 10. Analysing the formal architecture of pedological taxonomies, and comparing these with biological ones 11. Studying the cognitive bias of the human being when analysing natural resources and applying? taxonomies

Currently pedodiversity methods involve many mathematical tools, such as estimating pedorichness by extrapolation, entropic analysis, statistical distribution models for determining the structure of pedological assemblages, pedodiversity-area (time) relationships, nested subset analysis of pedological assemblages, pedotaxa-range-size distributions, scale invariance patterns (fractals and multifractals), and others.