Using the *.pdf version of C# in Depth, 3rd Edition I believe I've found a technical, coding mistake.

Page 534, in Table A.7 GroupBy examples:

The second line of code has a "Result" in column 2 of the table of:

Key: 4; Sequence: "zero", "four"
Key: 3; Sequence: "one", "two"
Key: 5; Sequence: "three"

I believe the way the line of associated code indicates the values should be all UPPERCASE:

"ZERO", "FOUR", etc.
Page 68, middle of page, is a code example. A portion of the code reads:

[Column(Name="ContactName"]

It is missing a closing parenthesis. It should read:

[Column(Name="ContactName")]

Message was edited by: Darach, 10/30/2014
The next to last paragraph - starting with "LINQ to XML makes...", the 2nd sentence, partial read, is:

"...than having to write of lot of code..."

should read
"...than having to write a lot of code..."

Message was edited by: Darach, 10/30/2014
Darach