In a short introduction, Gleeson outlines the different strokes needed to form each letter, and he briefly provides a history lesson about how kana developed.
Each page provides a stroke-by-stroke breakdown of a katakana character, including how the character looks in four different variations. Then he includes an area for you to practice, complete with trace-over guides. I recommend making copies of each page and practicing on these copies instead of in the workbook itself. Repetition is important!
After each katakana group, Gleeson provides practice loanwords. He also includes sections with Western names, city names (complete with maps), sports, instruments, food, electronics, and even Internet slang.