Several critics have commented on Alexander's writing style. In a "Horn Book" review of the Vesper Holly books, Ethel L. Heins stated that Alexander's writing was "elegant, witty, beautifully paced." Reviewers praised the action scenes in the Prydain chronicles, stating that they involved the reader in the scene without gruesome detail. One of Alexander's biographers, Jill P. May, stated that his prose changes depending on the goal of his work. While his fantasy style has been compared to J.R.R. Tolkien and C.S. Lewis, his later writings have a completely different style. His first work for children, a biography of a Jewish freedom fighter August Bondi, had little dialogue, perhaps in an effort to be faithful to historical sources. The fictional characters stood out more than Bondi's. Alexander wrote another biography for the Jewish Publication Society on Aaron Lopez. In absence of detailed historical sources, Alexander fictionalized more events in this work, with Lopez's fictional attitudes mirroring Alexander's.