The author opens with an anecdote from Alice in Wonderland which was appropriate, since I felt as though my world were being turned upside-down every time I took one of the practice quizzes. The quizzes in the practice exams accompanying this book are riddled with errors that invert the sense of the question: right answers become wrong and vice versa.
The author is very enamored of his informal/jokey authorial voice, but he (or his technical editor) should have spent more time editing the practice tests. I counted several critical errors, including:
* A question about google 'dorking' syntax with a typo, invalidating the syntax
* A question about null sessions where 2 of the 4 possible choices were character-for-character identical (allowing the reader to artificially eliminate those two)
* A question about XMAS scans where the 'quick answer' implies that identifying the scan as an XMAS scan is incorrect, but the in-depth answer section identifies the answer as correct.
* An omitted "NOT" that inverted the sense of the question
* A transposition of options A and B from the quiz portion to the detailed answer key, such that a student answering "A" would see that "B" was correct and believe he answered incorrectly.
* Use of the DNS term "SOA" where the XML term "SOAP" was intended.
* Transposition of the terms "covert" and "overt" in the answer key, such that a student seeking a correction will read and memorize an incorrect definition.
If you're using the practice exams to prepare for the CEH exam, set aside plenty of additional time to correct Walker's mistakes, and make sure that you don't take anything in the answers as authoritative; if you get a question "wrong", go verify the answer yourself. I am now wondering how many of my "right" answers were also typos, misleading me into a false sense of security ...
The quizzes are a useful review tool, but you'll need to spend about an hour after each 25-question quiz verifying the technical background for each answer. "All-in-One" is not accurate -- you're going to need at least one more authoritative source of information to prepare for the exam.