Errata

In the "Category" column of Table 2-3, the three bitwise operators shown below are labeled as "Logical" instead of "Bitwise" (which were correctly labeled earlier in the chapter in Numeric Types -> Specialized Operations on Integral Type).

Category Operator Operator Example User-overloadable
symbol name
Logical And & And x & y Yes
Logical Xor ^ Exclusive Or x ^ y Yes
Logical Or | Or x | y Yes

I really appreciate the link to Nullable Value Types and the preview

int? length = sb?.ToString().Length; // OK: int? can be null

BUT IT IS IN THE WRONG PLACE. Your first use of a nullable type occurs a few lines previous, which for me was on a previous kindle page:

char? c = foo?[1]; // c is null

It was a stumbler and I googled a while to get around what you nicely explain later. I suggest you move your explanation of nullable type up to the location where the concept is first used. Thanks!

The table has the same description for TakeLast and SkipLast, namely: "Takes only the last count elements". This seems to be an incorrect description for SkipLast.

For the switch statement, the author suggests using a discard (_) symbol, which is good, but it is also possible not to use any discard symbol to achieve the same result. Here's the book extract: "If you want to switch on a type, but are uninterested in its value, you can use a discard (_)
case DateTime _:"

This also works:
case DateTime:

It says casting from float to int loses fractional part without rounding. I found this is true only up to 2 decimal points. As soon as I added 3 9s after decimal it started rounding in float and in int.

The keyword list doesn't include <<with>> keyword which is mentioned on page no. 29.

It says "When you specify a constant, you’re restricted to the built-in integral
types; the bool, char, and enum types; and the string type." Actual it should say "... built-in numeric types;..." because switch works with real constants as well.

Considering the statement "The Contains method doesn’t offer the convenience of this overload, although you
can achieve the same result with the IndexOf method." C# 10 does have this overload and this is possible => "abcdef".Contains("aBc", StringComparison.InvariantCultureIgnoreCase)

Console.WriteLine ("ṻ".CompareTo ("ǖ")); // 0
Returns 1, not 0(zero).

DateTimeInfo should be DateTimeFormatInfo.

Paragraph, copied below, seems to suggest that != of float returns false when comparing 2 float.NaN or 1 float.NaN with a float value. But when == returns false, != returns true when one or both are float.NaN.

"Although it’s possible to overload != such that it means something
other than !(==), this is almost never done in practice,
except in cases such as comparing float.NaN."