75 ILCS 65/1
That the corporate authorities of cities and park districts, or any board of park commissioners having the control or supervision of any public park or parks, are hereby authorized to permit any free public library, organized under the terms and provisions of an act entitled, "An Act to encourage and promote the establishment of free public libraries in cities, villages and towns of this State," approved June 17, 1891, in force July 1, 1891, to erect and maintain, at its own expense, its library building within any public park now or hereafter under the control or supervision of such city, park district or board of park commissioners and to contract with any such free public library relative to the erection, maintenance and administration thereof. If any owner or owners of any lands or lots abutting or fronting on any such park, or adjacent thereto, or any other person or persons, have any right, easement, interest or property in such public park appurtenant to their lands or lots, or otherwise, which would be interfered with by the erection and maintenance of any free public library building, as hereinbefore provided, or any right to have such public park, or any part thereof, remain open and vacant and free from any buildings the corporate authorities of the city or park district or any board of park commissioners, having control of such park, may condemn the same in the manner prescribed for the exercise of the right of eminent domain under the Eminent Domain Act .
75 ILCS 65/1