Cluttered and unsystematic. Mercer has accumulated a lot of (photographs of) tools, but apparently refused to do any curation and just included everything regardless of whether he could come up with a credible or enlightening story to go along with the tool. Especially when it comes to Roman or East Asian tools, the results are messy; in the latter case, things aren't especially helped by his deep—though for the time (1920s) probably unremarkable—racism. The overwhelming majority of the tools are roughly 18th century American or Western European, though, as per the subtitle, though none will surprise anyone and Mercer's prose doesn't make for enjoyable consumption—he clearly fancies himself a poet, and, like every poet I've ever known, just manages to be a tedious git.
The main value of the book, then, is probably the novelty of Mercer labelling tools that are now once again popular or, at least, not especially rare as ``obsolete'' or ``superannuated'' (a word he especially loves and thinks means ``super duper obsolete''). One might hope that would give an insight into woodworking during the Interbellum, but since he also rates paring chisels among those, maybe not.