Thanks everybody for your assistance. I had looked over the search syntax table before and I found it rather hard to follow - it would help if there were a few more examples for each entry, especially how the syntax works when there are more constraints on the search than just the first level of filter. In my example above, for example, the syntax table gets me as far as stack:Topics for Botany Book" but doesn't tell me how to add the second level of filter that you have shown me in your (DTLow) answer - nothing in the Table would tell me to leave a space after "Topics for Botany Book" then write in tag:"Journals" followed by "some text" - there is no reference in the table at all to "some text".
I did follow the suggestion at the end of the Table to click the link to the "Search Grammar" section, which was helpful. With assistance from all off you, I finally got to what I am trying to do.
Then ... I think that maybe my question has been addressed in the latest update. I find now that when I search for a term in the Search Box, the first step is a Search across all Notebooks, but then (and I could not do this before) in the Results Box, there is now a Dropdown Menu that allows me to filter by Notebook. Exactly what I was struggling to do! Thanks everybody at Evernote for adding this feature, and thanks to those of you who helped me with your suggestions.