StarterPack: Microsoft BizTalk server

Why we need ? -
Integrate large business functions
Used when data needs to be transferred from one business unit to other, with in between  transformations as per the business requirements.

Wiki defines as -
Microsoft BizTalk Server (or simply "BizTalk") enables companies to automate business processes, through the use of adapters which are tailored to communicate with different software systems used in an enterprise. 

Initial stages -
2000 release - First version
2013 release - Currently used
First as the standard application server of Microsoft but when AppFabric was launched they decided to continue BizTalk as a integration app server.

Consists of -

1. Messages - These are in form of XML schema definition standard I.e. XSDs. All the documents are formed in parent child structure as in an XML and stored in BizTalk.

2. Transformation - done using Maps. Maps are implemented in XSLT language I.e.  XSLT (Extensible Stylesheet Language Transformations) is a language for transforming XML documents into other XML documents. Here we do mapping from one receive (input) doc to other format or same format send (output) doc.

3. Flow control and exception handling - Pipelines are used for this. These used pre defined components in BizTalk and act like a flowchart in the system flow.
Also what we have for controlling are Orchestration. These are implemented with the WS-BPEL compatible process language xLANG, (  Web Services Business Process Execution Language (WS-BPEL) . Orchestration is an component that controls the overall flow of Biztalk and automate process

4. Custom add-on - Not only these, we can add our own customized components like pipelines and custom functoids in maps using .Net assemblies.

In the box things -

1. BRE - Business rule engine. Helps to setup up rules as per requirements.
Wiki help - A business rules engine is a software system that executes one or more business rules in a runtime production environment. The rules might come from legal regulation ("An employee can be fired for any reason or no reason but not for an illegal reason"), company policy ("All customers that spend more than $100 at one time will receive a 10% discount"), or other sources

2. BAM - business activity monitoring .A system that visibly displays you all the activity happening at the back end.
Wiki help - Business activity monitoring (BAM) is software that aids in monitoring of business activities, as those activities are implemented in computer systems.

3. Admin console - the best thing, gives you an admin control that shows all your apps running their configurations and lots more.

4. Less coding more drag-drop 'ing - You don't need to be great at coding for this. Has inbuilt graphical power that helps you build the XML docs and XSLT maps just by dragging and dropping.

5. Automate it - Orchestrated solutions using orchestration. Helps you to automate things, apply rules and control the entire flow.

6. Web services - Yes, you can consume and expose your messages as web services and also WCF services with BizTalk.

7. EDI inbuilt -
Wiki help - Electronic Data Interchange (EDI) is an electronic communication method that provides standards for exchanging data via any electronic means. By adhering to the same standard, two different companies or organizations, even in two different countries, can electronically exchange documents (such as purchase orders, invoices, shipping notices, and many others). 

How's it organized - Architecture -

Has publish/subscribe architecture. Messages are published in BizTalk and can be consumed or subscribed by external events. This results in data loss save feature, because the data is stored in message box ( SQL comes into picture ) till we don't have an external events triggering it.
Wiki says - BizTalk makes processing safe by serialization (called dehydration in Biztalk's terminology) - placing messages into a database while waiting for external events, thus preventing data loss.

The core component - Adapter -

We use BizTalk to exchange info between 2 business entities and for this we need an ease of compatibility.
Thus BizTalk has adapters , it's a software component that helps in receiving and sending up files in and out of Biztalk server. Biztalk installs the pre defined native adapters by itself during default installation.
Great link here - https://msdn.microsoft.com/en-in/library/aa561360.aspx

That's all from the unboxing of the BizTalk server.
Go ahead and learn more .
Stay tuned.