The tracks are free. What am I paying for?
The tracks stay free forever. The Handbook is the same material re-made as something you own: 1,377 print-ready pages, offline, searchable, annotatable, plus cheatsheets and the AI Tutor Kit — none of which exist on the site.
What does “every 2026 update” mean?
New chapters, corrections and revisions published during 2026 are re-issued to you through the same download link. You do not buy anything again. When the edition rolls over, your copy keeps working — you simply own the 1.x line.
What format is it?
PDF, laid out for US Letter and readable on screen. The AI Tutor Kit is plain Markdown. No DRM, no reader app, no account required to open anything.
Can I expense it?
Yes — the receipt comes from our merchant of record and shows a normal software purchase. Most engineers do not need approval at this amount.
I am not in the US or Europe.
Purchasing-power pricing is available for lower-income countries at 40–60% off. Ask and it is yours; nobody is asked to prove anything.
What if it is not for me?
30 days, no questions asked. Email and it is refunded. You keep the files — chasing them down would cost more than the refund.