Polytechnic Preparatory Country Day School. Alumni Association.

The Brooklyn Collegiate and Polytechnic Institute was founded in 1854 and was the first all-boys school in Brooklyn. Located at 99 Livingston Street in the neighborhood of Brooklyn Heights, the Institute offered both preparatory and college level programs designed to be comparable to the most distinguished boarding schools of the day. By 1890, the Institute's Board of Trustees had decided to separate the Institute's preparatory and collegiate programs into two different schools, and in 1891 a new facility was constructed next to the Institute's original building to house the college, which took on the name of the Polytechnic Institute of Brooklyn. The preparatory program, which became the Polytechnic Preparatory School, remained at 99 Livingston Street.

Over time, the two schools took on increasingly distinctive and separate identities. The Polytechnic Institute of Brooklyn became a renowned college of engineering, and by the mid-20th century had become a coeducational institution. Throughout the late 20th and early 21st centuries, the Institute underwent several name changes, the first occuring in 1973 with the adoption of the name of the Polytechnic Institute of New York. A little over a decade later, the Institute became known simply as Polytechnic University. This name endured until 2008, when the Institute became affiliated with New York University and became the Polytechnic Institute of New York University (NYU). As of 2010, the Institute continues its affiliation with NYU and is located at Six Metrotech Center in Downtown Brooklyn, where it offers undergraduate and graduate degrees in several science disciplines, with a focus on engineering.

The Polytechnic Preparatory School relocated in 1916 to a 25-acre plot of land in the Brooklyn neighborhood of Dyker Heights, where it became incorporated as the Polytechnic Preparatory Country Day School, commonly known as Poly Prep. At its Dyker Heights location, Poly Prep grew into one of Brooklyn's esteemed private schools, and in the 1970s became a coeducational institution. In the 1990s, the School acquired property in the Brooklyn neighborhood of Park Slope, which it converted into the Poly Prep Lower School, a center of primary education. As of 2010, the School continues to offer private educational programs spanning early childhood through the twelfth grade at its Dyker Heights and Park Slope locations.

From the guide to the Brooklyn Collegiate and Polytechnic Institute collection, 1855-1981, (Brooklyn Historical Society)