Detailed, evidence-based help for common painful problems


If you have ever paid for access to a tutorial (e-book) on (or even many years ago when it was, you can login with your email and zip code as originally provided. If you can’t find your order this way, please contact me and I will look you up and get back to you quickly. ~ Paul Ingraham, Publisher


 ?Postal codes with spaces in them are tricky! The most common format (AA9 9AA) is not a problem: you can include the space, or not, doesn't matter. But please include spaces for any other format that normally contains them, like AA99 9AA or A9 9AA — your login is more likely to work.

Temporary warning! Are you a new customer, since March 30? This login will not work for you, unfortunately — if you don’t have your login link in your email inbox, you’ll need to contact me for assistance, and I’ll get back to you promptly. I’ll upgrade the login page so that it only asks for your email address ASAP. Meanwhile, all past customers should be able to use this login page as normal. ~ Paul Ingraham, Publisher

Shopping for more books? Adding to your library? You’re in the right place, because it’s best to login first. Without logging in — if you just go to the books page and place an order — you will still be recognized as a repeat customer by your email and zip code, but only if they match exactly. If you login here first, you can buy new books from your account page or the personalized customer information at the top of any of your existing books.

Privacy & Security of this form This login is private and secure: the information you submit is encrypted, used only used to search for a matching customer account, and then discarded. It’s a deliberate design choice not to use a “traditional” login.? The Google privacy popup in the lower-right is there only so I can use their “reCAPTCHA” service to prevent automated abuse of this form.

Standard, traditional authentication is based on the combination of a username and a password: two things that, in theory, only you know. But managing passwords is a pain in the neck (as we all know all too well). More security is more of a hassle. doesn’t need a lot of security, so it’s possible to login with less hassle: you only have to identify yourself with your email and zip/postal code, details that you don’t have to memorize or save just for this purpose.

Could someone else login to your account this way? These two pieces of information are much more knowable than a good username/password pair. In practice, however, not many “bad guys” know your email and zip code, or would try logging in with them here even if they did, and (most important of all) or can actually achieve anything by logging in here. Successfully logging in to someone’s account here doesn’t get anyone much of anything, usually just a free book they don’t need. 😉 So the stakes are low — I am not protecting your life savings here.

The goal of the access system on is to have security that’s just casual enough that no one has to worry about saving a password, but still good enough to prevent abuse. I think I’ve achieved that balance, but feedback is always welcome if you are concerned about it.