From the beginning Kubiëna thought that the microscope had to be employed in the study of soils, because it is a whole, and its partial or modified study did not allow its global knowledge. This led him to develop a procedure for observing the soil without disturbing it, developing a sampling technique (called Kubiena boxes) and to prepare thin sections for its observation and study. According to Kubiena, different soil types should have different microstructures that would serve for their characterization. With these ideas he began his explorations around the world to study the soils, always accompanied by a small microscope to recognize them in the field.
This document includes a literal transcription of the manuscript completed in 2002 by Drs. Benayas and Martin Ramos on the work of Prof. Kubiëna, as well as the photographs of the collection trays made by Mr. Antonio Jorge (2014). The greatest scientific value of the present publication is mainly due to the cooperation of Prof. Carlos Dorronsoro (Department of Soil Science, Univ. of Granada), who made the navigable macroimages and microphotographs (2014-2015).