As dusk fell, Asha realized the PDF had done more than teach her methods; it had offered a companionable mentor on a rainy evening. She made a plan: summarize the key examples, redo the proofs by hand, and apply one model to her housing data for her upcoming assignment. Before closing the laptop, she saved the scanned PDF into a folder titled “econometrics — classics,” and added a new sticky note: “Ask Prof. Kim about Maddala’s IV example.”