This new web site is a wonderful resource for anyone interested in the anatomy of central European woods, and, given that the genera included in this site occur elsewhere in the northern hemisphere, it will be useful outside of central Europe.
The home page of the site states: "This Web-based identification key is a completely revised (text, key) and updated (more and new photographs and new anatomic items) version of the book by Schweingruber F.H., 1990: Microscopic Wood Anatomy; Structural variability of stems and twigs in recent and subfossil woods from Central Europe. 3rd edition 1990. Birmensdorf, Eidgen–ssische Forschungsanstalt WSL."
As you would expect, given the original publication, the images are excellent. The navigation of the site fits the definition of user-friendly. There are pages "Macroscopic characteristics" and "Microscopic characteristics" that provide an introduction to terminology, with an illustrated glossary and comments on the diagnostic value of different characteristics. There are multiple ways to get to species descriptions with 1) multiple images, particularly of transverse sections, to illustrate within species variation, 2) brief descriptions of the features visible in each plane of view, and 3) comments on diagnostic features, including comments such as "The wood of the three Quercus species (Q. robur, Q. petraea, Q. pubescens) cannot be differentiated on the basis of their wood anatomy."
Thumbnails on the species pages are "live" and provide access to larger images. "Species list" is alphabetical by genus and species list of all species (about 130), "Coniferous wood" and "Dicotyledon wood" list species for those groups.
The identification key is a synoptic key, with characteristics presented in tabular form. From the key you can access definitions and images for the key characters. It took me a bit time to realize that "Wood types" at the top of the key was a pull-down menu to take you to the major subdivisions within the table: Coniferous wood, Ring-porous wood, Diffuse- and semi-ring-porous wood, Diffuse- and semi-ring-porous wood with aggregate rays.
This site is valuable, as was the 1990 book, for showing both the variability of wood as well as documenting what many find an unpleasant fact, namely that many tree species share similar wood anatomy. For any one who teaches wood anatomy, this is a most useful resource. The site is a model for attractiveness and usability.