In Pennsylvania, eminent domain is defined as "[t]he power of the Commonwealth to take private property for public use in return for just compensation" 26 Pa.C.S.A. § 202.
The Pennsylvania Eminent Domain Code was first adopted in 1964 (1964, P.L. 84, No. 6 / legislative history) and consolidated in 2006 (2006, P.L. 112, No. 34 / legislative history). It has been amended multiple times and can be found in Title 26 of the Pennsylvania Consolidated Statutes.
A classic Pennsylvania treatise on eminent domain is the Bisel book Snitzer Pennsylvania Eminent Domain. The first edition was published in 1964 and is noted as being the first treatise to directly discuss the topic. The table of contents to the current edition can be found on the publisher's website.
Encyclopedic sets also cover eminent domain. The Pennsylvania Law Encyclopedia devotes a large portion of volume 23 to the topic. The PLE is available to Jenkins members on their desktops via the LexisNexis Digital Library. It is also available on the library's Lexis computers, as well as in print in the library.
The Summary of Pennsylvania Jurisprudence also has a chapter devoted to eminent domain. See the Property volumes, chapter 11. This title is available on the library's Westlaw computers as well as in print in the library.
Both the Pennsylvania Bar Institute and the National Business Institute publish CLE materials related to eminent domain. A list of those available at Jenkins can be found by searching the Jenkins' catalog for eminent domain.