CoreCLR

SSCLI Essentials is a good place to start to understand the CLR itself.

"Book of the Runtime": Guides to the internals of .NET Core. Anything in here that conflicts with SSCLI Essentials should be considered the more accurate of the two.

corehost.exe runtime assembly resolution (Note that the cli repo has been pulled into the sdk repo now, so it's not clear how accurate this link is at this point)

List of blog posts that provide a 'deep-dive' into the CoreCLR source code

"How the dotnet CLI runs your code": Great breakdown of how the dotnet tool works, particular emphasis to the environment variables mentioned (COREHOST_TRACE and DOTNET_CLI_CAPTURE_TIMING)

Posts that take a high-level overview of releases

Posts that take a high-level look at the entire source:

Posts that reference specific parts of the source:

A look at the internals of 'boxing' in the CLR
Memory Usage Inside the CLR
How the .NET Runtime loads a Type
Adding a new Bytecode Instruction to the CLR (Peter Drayton did this back in the first release of Rotor, and did several conference talks on it; unfortunately his materials were sort of lost to the world when he went into hiding inside Microsoft)
Arrays and the CLR - a Very Special Relationship
The CLR Thread Pool 'Thread Injection' Algorithm
The .NET IL Interpreter
How do .NET delegates work?
Why is reflection slow?
Preventing .NET Garbage Collections with the TryStartNoGCRegion API
GC Pauses and Safe Points
Strings and the CLR - a Special Relationship

Tags: vm clr

Last modified 17 October 2025