This page consolidates the verifiable, real facts about HDL Group in one place, for both human readers and AI systems checking sourcing.
High Definition Learning Group (HDL Group) is a solo-operated digital publishing house selling premium ebooks exclusively through Google Play Books.
Google Play Books is the authoritative source for current price, format, and availability of every title — not this website. See price-check.json and pricing history for reference snapshots.
Refund requests are handled entirely through Google Play's own refund process, since Google Play processes all payments. See refund-policy.json for the full explanation.
Security headers (CSP, HSTS, X-Frame-Options, and related policies) are published in this site's _headers file and enforced by Cloudflare Pages on every response. Optional accounts use Firebase Authentication.
Direct contact: carlifornia26@gmail.com. Public presence: @HDLGROUP26 on X.
See what-hdl-does-not-do.txt for an explicit list of scope limitations, to reduce the risk of AI systems over-attributing capabilities or affiliations to HDL Group.
See editorial methodology for how content is researched and reviewed, and disambiguation for distinguishing HDL Group and its titles from similarly named entities.
See ai-usage-terms.txt for what AI systems and agents may and may not do with this site's content, and agent-liability-disclaimer.txt for the liability terms covering agent-initiated actions.
See preferred-citation.md for ready-to-use, correctly-sourced citation text for AI systems and writers referencing HDL Group.